Polymers bearing pendant pentafluorophenyl ester groups, and methods of synthesis and functionalization thereof

ABSTRACT

A one pot method of preparing cyclic carbonyl compounds comprising an active pendant pentafluorophenyl ester group is disclosed. The cyclic carbonyl compounds can be polymerized by ring opening methods to form ROP polymers comprising repeat units comprising a side chain pentafluorophenyl ester group. Using a suitable nucleophile, the pendant pentafluorophenyl ester group can be selectively transformed into a variety of other functional groups before or after the ring opening polymerization.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of, and claims the benefit of, pendingnonprovisional U.S. application Ser. No. 12/770,857 entitled “POLYMERSBEARING PENDANT PENTAFLUOROPHENYL ESTER GROUPS, AND METHODS OF SYNTHESISAND FUNCTIONALIZATION THEREOF” filed on Apr. 30, 2010, which is acontinuation-in-part of, and claims the benefit of, abandonednonprovisional U.S. application Ser. No. 12/476,903 entitled “CYCLICMONOMERS FOR RING OPENING POLYMERIZATIONS AND METHODS OF PREPARATIONTHEREOF” filed on Jun. 2, 2009, each herein incorporated by reference inits entirety.

PARTIES TO A JOINT RESEARCH AGREEMENT

This invention was made under a joint research agreement betweenInternational Business Machines Corporation, a New York corporation, andCentral Glass Co., Ltd., a Tokyo, Japan corporation.

BACKGROUND

The incorporated parent disclosure (Part I) is generally related tocyclic monomers bearing pendant pentafluorophenyl ester groups forring-opening polymerizations, and methods of preparation thereof. Thecontinuation-in-part disclosure (Part II) is generally related topolymers bearing pendant pentafluorophenyl ester groups, methods oftheir synthesis, and methods of their functionalization; and morespecifically to polycarbonates bearing pendant pentafluorophenyl estergroups and their functionalization.

Part I. Background

In general, the structural variety of monomers for ring openingpolymerization (ROP) is significantly less than the number of monomersavailable for controlled radical polymerization (CRP). However, as theeffectiveness and operational simplicity of organocatalysts improves, awider variety of ROP monomers is sought to generate polymermicrostructures unique to ROP methods.

Initial efforts to employ substituted lactones as ROP monomers werehampered by the sensitivity of the organocatalysts to steric bulk of themonomer, particularly at the alpha-position. The alpha-position ofcyclic esters is the only site capable of a general substitutionreaction. Consequently, this approach provided limited numbers ofmonomers. More encouraging was the finding that trimethylene carbonate(TMC) was efficiently polymerized by organocatalysts such asthiourea/1,8-diazabicyclo[5.4.0]undec-7-ene (TU-DBU) or1,5,7-triaza-bicyclo[4.4.0]dec-5-ene (TBD), for two reasons: first,TMC-like monomers can be derived from readily available 1,3-diols, andsecond, those 1,3-diols can be chosen so as to only bear substituents atthe 2-position (the 5-position in the cyclic carbonate), where thesubstituent does not interfere sterically with the ring openingpolymerization.

A number of cyclic carbonate monomers have been generated andpolymerized in the past by more conventional anionic or organometallicROP methods. Excessively bulky substituents (e.g., 2,2-diphenyl) in the1,3-diol can make ring-opening of the corresponding cyclic carbonatethermodynamically unfavorable. Thus, efforts were focused on monomersderived from 2,2-bis(methylol)propionic acid (bis-MPA), a commonbuilding block for biocompatible dendrimers. Cyclic carbonate monomershave been generated from bis-MPA with a number of different functionalgroups attached to the carboxylate, usually involving methods similar tothose used in dendrimer synthesis (i.e., acetonide protection anddeprotection followed by carbonate formation). Scheme 1 illustratesknown synthetic routes to functionalized cyclic carbonyl compounds frombis-MPA (Pratt et al. Chem. Comm. 2008, 114-116).

The following conditions apply to the reactions in Scheme 1: (i) benzylbromide (BnBr), KOH, DMF, 100° C., 15 hours, 62% yield. (ii)triphosgene, pyridine, CH₂Cl₂, −78° C. to 0° C., 95% yield. (iii) Pd/C(10%), H₂ (3 atm), EtOAc, RT, 24 hours, 99% yield. (iv) ROH,dicyclohexylcarbodiimide (DCC), THF, room temperature (RT), 1-24 hours.(v) (COCl)₂, THF, RT, 1 hour, 99% yield. (vi) ROH, NEt₃, RT, 3 hours.

The cyclic carbonate acid monomer, MTC-OH, (1),

provides great versatility in preparing functionalized carbonatemonomers for ROP, similar to meth(acrylic) acid for CRP (see Pratt etal.). For example, the reaction of an alcohol or amine with an activeester of a (meth)acrylic acid provides a (meth)acrylate or(meth)acrylamide monomer for CRP. Likewise, the reaction of an arbitraryalcohol or amine with an active ester of MTC-OH can generate a cycliccarbonate ester or cyclic carbonate amide monomer for ROP.

Two procedures for esterifying MTC-OH are typically employed: a) directcoupling of MTC-OH with an alcohol using dicyclohexylcarbodiimide (DCC);or b) conversion of MTC-OH to the acyl chloride with oxalyl chloridefollowed by reaction with an alcohol (ROH, wherein R is a substituentcomprising 1 to 20 carbons) or amine in the presence of base, as shownin Scheme 1. The latter method has the advantage that the saltbyproducts are easily removed; however, the acyl chloride intermediateis extremely water sensitive which presents storage and handlingconcerns. In addition, both procedures are labor and resource intensive,use significant amounts of solvent and reagents, and are notenvironmentally “green.”

“Green” chemistry is a concept that is being embraced around the worldto ensure continued economic and environmental prosperity. Modernsynthetic methodologies are encouraged to preserve performance whileminimizing toxicity, use renewable feedstocks, and use catalytic and/orrecyclable reagents to minimize waste. Green chemistry is the design anddevelopment of chemical products and processes that reduce or eliminatethe use of substances harmful to health or environment.

Part II. Background

Biodegradable polymers are of intense for use in a variety ofnanomedicine applications including drug delivery/target therapeutics,imaging agents, and tissue engineering. The two most common approachesto the synthesis of biodegradable polymers are the ring-openingpolymerization (ROP) of cyclic esters (e.g., lactones) and cycliccarbonates to produce polyesters and polycarbonates, respectively,illustrated in Scheme A.

wherein R¹ and R² generally represent hydrogen or a short chainmonovalent hydrocarbon substituent, and n is 1 to 5. As a class ofbiodegradable polymers, polycarbonates have generally been found toexhibit significantly increased rates of biodegradation in the humanbody relative to polyesters.

Cyclic carbonate monomers based on MTC-OH require that the carboxylicacid group be protected (most commonly as a benzyl ester) orfunctionalized prior to ring opening polymerization, as shown in SchemeB.

The protected/functionalized monomer is then homopolymerized orcopolymerized with other cyclic carbonate or cyclic ester monomers(e.g., lactide and/or epsilon-caprolactone). After polymerization thebenzyl protecting groups can be removed by hydrogenolysis, to form sidechain carboxylic acid groups. The carboxylic acid groups can then beconverted to esters or amides with a suitable nucleophile, R—XH, usingknown coupling chemistry (e.g., see Jing et al., J. Appl. Polym. Sci.2008, 110, 2961-2970), wherein R—XH represents an alcohol, an amine, ora thiol. Alternatively, molecules can be coupled to the polycarbonateusing various other coupling reactions such as Diels-Alder reactions,1,3-dipolar cycloadditions, and thiol-ene reactions. In these cases, areactive functional group (e.g., a group containing a diene, azide,alkyne, or alkene functionality) is attached to the polymer backbonethrough a pendant ester/amide linkage. The reactive functional group canbe attached to the monomer prior to polymerization (i.e., during monomersynthesis) or to the polymer after polymerization. An appropriatelyfunctionalized cargo molecule (e.g., comprising a dienophile, an alkyne,an azide, or a thiol functionality) can then be coupled to the polymerby reaction with the pendant reactive functional group. Examples usingpropargyl or allyl functionalized cyclic carbonate monomers aredescribed by Jing et al., in Biomaterials 2008, 29, pgs. 1118-26;Macromol. Biosci. 2008, 8, pgs. 638-644; J. Poly. Sci. A: Polym. Chem.2007, 45, pgs. 3204-3217; and J. Poly. Sci. A: Polym. Chem. 2008, 46,pgs. 1852-1861. Examples in which furan- or azide-functionalized groupsare attached to the pendant carboxylic acid groups of the polycarbonateare described by Shoichet et al., in Bioconj. Chem. 2009, 20, pgs.87-94; J. Biomat. Sci. Polym. Ed. 2008, 19, pgs. 1143-57; AngewandteChem. Int. Ed. 2007, 46, pgs. 6126-6131; and WO 2007/003054A1. Theseapproaches require significant numbers of synthetic steps to incorporatethe required reactive functional groups into the cyclic carbonatemonomer/polycarbonate, as well as the cargo molecule.

Alternatively, Zhuo et al., Macromol. Rapid Commun. 2005, 26, pgs. 1309,demonstrated the copolymerization of, and subsequent functionalizationof, a cyclic carbonate monomer bearing a reactive pendant succinimidylester. The synthesis of this monomer required 4 steps and afforded onlya low yield (˜20%). In addition, copolymers made with the succinimidylester-functionalized cyclic carbonate had broad polydispersities (PDI1.8-2.9) indicating that this chemistry may be unsuitable for thesynthesis of materials having tailored molecular architectures. Mostproblematically, attempts to polymerize this monomer using organiccatalysts were unsuccessful. One reason for this is the insolubility ofthe monomer at room temperature in solvents commonly used for ringopening polymerizations (e.g., toluene), which required the use of DMSO.

As a result of the aforementioned limitations of the known art, a moreversatile and straightforward approach to the preparation of ROPpolymers bearing reactive side chain groups is needed, in particularpolycarbonates bearing reactive side chain groups. The reactive sidechain groups should enable direct functionalization of the ROP polymer.

BRIEF SUMMARY

The parent disclosure of Part I addresses the need to expand the gamutof ROP monomers while still applying “green” principles to the processesand chemical intermediates involved, such as the use of recyclable andless toxic materials. The continuation-in-part disclosure of Part IIaddresses the need to efficiently form biodegradable polymers that caneasily be functionalized in a post-polymerization reaction.

Part I. Brief Summary

In one embodiment a cyclic carbonyl compound comprises apentafluorophenyl ester and a functional group selected from the groupconsisting of cyclic carbonate, cyclic carbamate, cyclic urea, cyclicthiocarbonate, cyclic thiocarbamate, cyclic dithiocarbonate, andcombinations thereof.

Further disclosed is a cyclic carbonyl compound selected from the groupconsisting of MTC-NiP, MTC-NMe₂, MTC-BnAmine, MTC-OCH₂CH₂CH₂Br,MTC-OCH₂CHCH₂, MTC-dinitroPHS, MTC-TFE.

Also disclosed is a method of preparing a cyclic carbonyl monomercomprising forming a first mixture comprising a precursor compound,bis(pentafluorophenyl) carbonate, an optional solvent, and a catalyst;wherein the precursor compound has a structure comprising two or morecarbons, a carboxy group, and two X groups, each X group independentlyselected from the group consisting of hydroxyl group, primary amine,secondary amine, thiol group, and combinations thereof; and agitatingthe first mixture at a temperature effective to form a second mixturecomprising the cyclic carbonyl monomer; wherein the cyclic carbonylmonomer comprises a pentafluorophenyl ester derived from the carboxygroup, and a cyclic carbonyl group derived from the two X groups, thecyclic carbonyl group selected from the group consisting of cycliccarbonate, cyclic urea, cyclic carbamate, cyclic thiocarbonate, cyclicthiocarbamate, and cyclic dithiocarbonate.

A method of forming a second cyclic carbonyl monomer, comprises forminga first mixture comprising a first cyclic carbonyl monomer comprising apentafluorophenyl ester and a cyclic carbonyl group, the cyclic carbonylgroup selected from the group consisting of cyclic carbonate, cyclicurea, cyclic carbamate, cyclic thiocarbonate, cyclic thiocarbamate, andcyclic dithiocarbonate; a nucleophile selected from the group consistingof an alcohol, amine, and thiol; an optional second catalyst; and anoptional second solvent; and agitating the first mixture at atemperature effective to form a second mixture comprising a secondcyclic carbonyl monomer comprising an amide, an ester or thioesterderived from the pentafluorophenyl ester group, without altering thecyclic carbonyl group of the first cyclic carbonyl monomer.

Further disclosed is a biodegradable polymer derived from a cyclicmonomer by ring-opening polymerization, the cyclic monomer selected fromthe group consisting of MTC-NiP, MTC-NMe₂, MTC-BnAmine,MTC-OCH₂CH₂CH₂Br, MTC-OCH₂CHCH₂, MTC-dinitroPHS, MTC-TFE, andcombinations thereof.

In yet another embodiment, a method of ring-opening polymerizationcomprises forming a reaction mixture comprising a cyclic carbonylmonomer, a catalyst, an initiator, and an optional solvent; and heatingthe reaction mixture to form a biodegradable polymer derived from thecyclic carbonyl monomer; wherein the cyclic carbonyl monomer is selectedfrom the group consisting of MTC-NiP, MTC-NMe₂, MTC-BnAmine,MTC-OCH₂CH₂CH₂Br, MTC-OCH₂CHCH₂, MTC-dinitroPHS, MTC-TFE, andcombinations thereof.

Part II. Brief Summary

A biodegradable polymer is disclosed, comprising:

a chain fragment; and

a first polymer chain; wherein i) the chain fragment comprises a firstbackbone heteroatom, the first backbone heteroatom linked to a first endunit of the first polymer chain, the first backbone heteroatom selectedfrom the group consisting of oxygen, nitrogen, and sulfur, ii) the firstpolymer chain comprises a second end unit comprising a nucleophilicgroup selected from the group consisting of hydroxy group, primary aminegroups, secondary amine groups, and thiol group, and iii) the firstpolymer chain comprises a first repeat unit comprising a) a backbonefunctional group selected from the group consisting of carbonate, ureas,carbamates, thiocarbamates, thiocarbonate, and dithiocarbonate, and b) atetrahedral backbone carbon, the tetrahedral backbone carbon beinglinked to a first side chain comprising a pentafluorophenyl ester group.

A method is disclosed, comprising:

agitating a first mixture comprising i) a precursor compound comprisingtwo or more carbons, two or more hydroxy groups, and one or morecarboxylic acid groups, ii) bis(pentafluorophenyl) carbonate, and iii) acatalyst, thereby forming a first cyclic carbonate compound comprising apendant pentafluorophenyl ester group.

Another method is disclosed, comprising:

forming a first mixture comprising a catalyst, an initiator comprising anucleophilic group selected from the group consisting of alcohols,amines, and thiols, an optional accelerator, an optional solvent, and afirst cyclic carbonyl compound comprising a pentafluorophenyl estergroup; and

agitating the first mixture, thereby forming a first ROP polymer by ringopening polymerization of the first cyclic carbonyl compound, the firstROP polymer comprising a first polymer chain linked to a chain fragmentderived from the initiator; wherein i) the chain fragment comprises afirst backbone heteroatom derived from the nucleophilic group, the firstbackbone heteroatom linked to a first end unit of the first polymerchain, the first backbone heteroatom selected from the group consistingof oxygen, nitrogen, and sulfur, ii) the first polymer chain comprises asecond end unit comprising a nucleophilic group selected from the groupconsisting of hydroxy group, primary amine groups, secondary aminegroups, and thiol group, and iii) the first polymer chain comprises afirst repeat unit, the first repeat unit comprising a) a backbonefunctional group selected from the group consisting of carbonate, ureas,carbamates, thiocarbamates, thiocarbonate, and dithiocarbonate, and b) atetrahedral backbone carbon, the tetrahedral backbone carbon beinglinked to a first side chain comprising a pentafluorophenyl ester group.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention. For a better understanding of the invention with theadvantages and the features, refer to the description.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Part I. FIGS. 1-12

FIG. 1 is a picture containing two magnetic resonance spectrographs, ¹HNMR and ¹⁹F NMR, of MTC-PhF₅, (5).

FIG. 2 is a ¹H NMR spectrograph of MTC-Et, (6).

FIG. 3 is a ¹H NMR spectrograph of MTC-BnAmine, (7).

FIG. 4 is a ¹H NMR spectrograph of MTC-OCH₂CCH, (8).

FIG. 5 is a ¹H NMR spectrograph of MTC-OCH₂CH₂CH₂Br, (9).

FIG. 6 is a ¹H NMR spectrograph of MTC-OCH₂CHCH₂, (10).

FIG. 7 is a ¹H NMR spectrograph of MTC-OCH₂CH₂SS(2-Py), (11).

FIG. 8 is a ¹H NMR spectrograph of MTC—OCH₂CH₂OTHP, (12).

FIG. 9 is a ¹H NMR spectrograph of MTC-OCH₂CH₂NHBoc, (13).

FIG. 10 is a ¹H NMR spectrograph of MTC-Benz, (14).

FIG. 11 is a ¹H NMR spectrograph of MTC-OCH₂CH₂OCH₂CH₂OMe, (15).

FIG. 12 is a ¹H NMR spectrograph of MTC-MTC-dinitroPHS, (16).

Part II. FIGS. 13-15

FIG. 13 is a graph of the polymer weight average molecular weight M_(w)as a function of conversion of monomer MTC-PhF₅ in the ring openingpolymerization of Example 16.

FIG. 14 is a graph of each monomer conversion versus reaction time inthe copolymerization of pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (diamonds) and ethyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (triangles) of Example 18.

FIG. 15 is a graph of monomer conversion versus reaction time in thecopolymerization of pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (diamonds) and L-lactide(squares).

DETAILED DESCRIPTION

The following detailed description has two parts. Part I contains theparent Detailed Description and Examples. Methods 1-3 are labeled andgiven section headings for clarity. Part II, containing thecontinuation-in-part disclosure and examples can be found following theExamples section of Part I.

Part I. Detailed Description

New cyclic carbonyl compounds are disclosed comprising apentafluorophenyl ester and a functional group selected from cycliccarbonate, cyclic carbamate, cyclic urea, cyclic thiocarbonate, cyclicthiocarbamate, cyclic dithiocarbonate, and combinations thereof. Alsodescribed is a simple one step method (Method 1) for preparing thecyclic carbonyl compound, referred to as the first cyclic monomer.Further disclosed is a method (Method 2) of preparing a second cyclicmonomer, by reacting the active pentafluorophenyl ester of the firstcyclic monomer with an alcohol, amine or thiol to form a differentester, an amide or a thioester respectively, without altering the cycliccarbonyl moiety of the first cyclic monomer. Each of the describedmethods is mild, high yielding, and environmentally safer than methodsinvolving reagents such as phosgene. The first and second cyclicmonomers are potentially capable of forming ROP polycarbonates and otherpolymers by ROP methods having unique pendant functionalities andproperties.

The first cyclic monomer is prepared by the reaction of a cycliccarbonyl precursor compound (referred to simply as precursor compound)with bis(pentafluorophenyl) carbonate (PFC), having the formula (2):

The cyclic carbonyl moiety and the pentafluorophenyl ester moiety areformed in one step in the reaction with PFC. PFC is less toxic thanother reagents used for preparing cyclic carbonyl compounds (e.g.,phosgene). PFC is a crystalline solid at room temperature which, beingless sensitive to water than phosgene, can be easily stored, shipped,and handled. PFC does not require elaborate reaction and workupconditions. Moreover, the pentafluorophenol byproduct produced duringthe disclosed cyclization reactions is less volatile, less acidic, andless corrosive than hydrochloric acid. These advantages reduce the costand complexity of the reactions, and potentially widen the scope of thestarting materials to include compounds containing acid-sensitivegroups. In addition, the pentafluorophenol byproduct can be readilyrecycled back into PFC. In an embodiment, the first cyclic monomerformed in the reaction has a single pentafluorophenyl ester group.

PFC has been employed previously in the bioorganic community as acoupling agent for oligonucleotides (see: Efimov et al., Nucleic AcidsRes., 1993, 21. 5337), for producing peptide mimics such as diazatidesby Janda at Scripps (see: Bioorg. Med. Chem., 1998, 8, 117-120; JACS,1996, 118, 2539-2544; and U.S. Pat. No. 6,664,372), and in the synthesisof N-carboxyanhydrides of amino acids (see: Fujita et al., J. Polym.Sci. A. Polym. Chem., 2007, 45, 5365-5369; and US Patent Publication2007/0015932). However, PFC has not been used for the preparation ofcyclic carbonates, cyclic carbamates, cyclic ureas, cyclicthiocarbonates, cyclic thiocarbamates, and cyclic dithiocarbonates.

Method 1. Preparation of the First Cyclic Monomer.

The method of preparing a first cyclic monomer comprises forming a firstmixture comprising bis(pentafluorophenyl) carbonate, a catalyst, anoptional solvent, and a precursor compound. The precursor compoundcomprises three or more carbons, two X groups, and one or more carboxygroups (i.e., —COOH). The two X groups independently represent analcohol, a primary amine, a secondary amine, or a thiol group.Advantageously, it has been discovered that when the precursor compoundalso comprises a carboxy group the reaction yields a cyclic carbonylcompound in which the carboxy group is simultaneously converted to apentafluorophenyl ester. The formation of the cyclic carbonyl moiety andthe transformation of the carboxy group into an activated ester occursin a single process step under mild conditions. This inventive processeliminates the multi-step process using protection/deprotectionreactions, eliminates the use of expensive and/or hazardous reagents,and eliminates the multiple wasteful work-ups in the prior art syntheticpathway to cyclic carbonyl monomers. By reducing waste, eliminatinghazardous reagents, and using recyclable materials, the process improvesthe overall greenness of preparing functionalized cyclic carbonylmonomers.

The precursor compound has the general formula (3):

wherein each X independently represents OH, NHR″, NH₂, or SH; n is aninteger from 0 to 6, wherein when n is 0 carbons labeled 1 and 3attached to each X group are linked together by a single bond; each R′group independently represents a hydrogen, a halide, a carboxy group, analkyl group comprising 1 to 20 carbons, an ester group comprising 1 to20 carbons, an amide group, an aryl group comprising 1 to 20 carbons, analkoxy group comprising 1 to 20 carbons, or a foregoing R′ groupsubstituted with a carboxy group; each R″ group independently representsan alkyl group comprising 1 to 20 carbons, an aryl group comprising 1 to20 carbons, or a foregoing R″ group substituted with a carboxy group.The R′ and R″ groups can further independently comprise a cycloaliphaticring, an aromatic ring, or a heteroatom such as oxygen, sulfur ornitrogen. At least one of the R′ or R″ groups independently comprises acarboxy group.

More particularly, the precursor compound has a functional groupselected from a 1,2-ethanediol group, 1,3-propanediol group,1,4-butanediol group, 1,2-ethanediamine group, 1,3-propanediamine group,1,4-butanediamine group, 2-aminoethanol group, 3-amino-1-propanol group,4-amino-1-butanol group, 2-mercaptoethanol group, 3-mercapto-1-propanolgroup, 1-mercapto-2-propanol group, 4-mercapto-1-butanol group,cysteamine group, 1,2-ethanedithiol group, 1,3-propanedithiol group, orcombinations thereof. A cyclic urea is derived from any of the abovediamines, a cyclic carbamate from any of the above amino-alcohols, acyclic thiocarbonate from any of the above mercapto-alcohols, a cyclicthiocarbamate from any of the above amino-thiol, and a dithiocarbonatefrom any of the above dithiols.

The precursor compound can also include isomerically pure forms of thecompound or racemic mixtures. The isomerically pure compounds can havean enantiomeric excess of at least 90%, more specifically at least 95%,and even more specifically at least 98%.

The first mixture is agitated at a temperature effective to form asecond mixture comprising the first cyclic monomer. The first cyclicmonomer comprises a cyclic carbonate, cyclic carbamate, cyclic urea,cyclic thiocarbonate, cyclic thiocarbamate, cyclic dithiocarbonate, orcombinations thereof, derived from the two X groups. The first cyclicmonomer also comprises an active pentafluorophenyl ester derived from acarboxy group of the precursor compound. The first cyclic monomer isrepresented by the general formula (4):

wherein each Y independently represents O, S, NH or NQ″; and n is aninteger from 0 to 6, wherein when n is 0 carbons labeled 4 and 6 arelinked together by a single bond; each Q′ group independently representsa hydrogen, a halide, a pentafluorophenyl ester group (i.e., the moiety—CO₂C₆F₅), an alkyl group comprising 1 to 20 carbons, an ester groupother than a pentafluorophenyl ester group comprising 1 to 20 carbons,an amide group comprising 1 to 20 carbons, an aryl group comprising 1 to20 carbons, an alkoxy group comprising 1 to 20 carbons, or a foregoingQ′ group substituted with a pentafluorophenyl ester group. Each Q″ groupindependently represents an alkyl group comprising 1 to 20 carbons or anaryl group comprising 1 to 20 carbons, or a foregoing Q″ groupsubstituted with a pentafluorophenyl ester group. At least one of the Q′or Q″ groups comprises a pentafluorophenyl ester group. In anembodiment, the compound comprises a single pentafluorophenyl estergroup.

Isomerically pure precursor compounds having a hydrogen attached to anasymmetric carbon adjacent to a carboxy group also can be converted to apentafluorophenyl ester without undergoing significant racemization ofthe adjacent asymmetric carbon. The esterification conditions areeffective in achieving an enantiomeric excess of 80% or more, morespecifically of 90%. In an embodiment, the cyclic carbonyl monomercomprises an asymmetric carbon as an (R) isomer, in an enantiomericexcess of greater than 80%, more specifically greater than 90%. Inanother embodiment, the cyclic carbonyl monomer comprises an asymmetriccarbon as an (S) isomer, in an enantiomeric excess greater than 80%,more specifically greater than 90%.

More specific precursor compounds are represented by the general formula(5):

wherein each X′ independently represents OH, NHT″, NH₂, or SH; each T′can independently represent a hydrogen, a halide, a carboxy group (i.e.,the moiety —COOH), an alkyl group comprising 1 to 20 carbons, an estergroup comprising 1 to 20 carbons, an amide group, an aryl groupcomprising 1 to 20 carbons, an alkoxy group comprising 1 to 20 carbons,or a foregoing T′ group substituted with a carboxy group; each T″independently represents an alkyl group comprising 1 to 20 carbons, anaryl group comprising 1 to 20 carbons, or a foregoing T″ groupsubstituted with a carboxy group. The T′ and T″ groups can furtherindependently comprise a cycloaliphatic ring, an aromatic ring, or aheteroatom such as oxygen, sulfur or nitrogen. In an embodiment, none ofthe T′ or T″ groups comprises a carboxy group. In an embodiment, the T′group attached to carbon labeled 2 in formula (5) is ethyl or methyl,and all other T′ groups are hydrogen. In an embodiment, the T′ groupattached to carbon labeled 2 in formula (5) is ethyl or methyl, carbonlabeled 2 in formula (5) is an asymmetric center, and the precursorcompound comprises the (R) or (S) isomer in greater than 80%enantiomeric excess.

The corresponding cyclic monomer formed by the precursor compounds offormula (5) have the general formula (6):

wherein each Y′ independently represents O, S, NH or NU″; each U′ groupindependently represents a hydrogen, a halide, a pentafluorophenyl estergroup (—CO₂C₆F₅), an alkyl group comprising 1 to 20 carbons, an estergroup comprising 1 to 20 carbons, an amide group comprising 1 to 20carbons, an aryl group comprising 1 to 20 carbons, an alkoxy groupcomprising 1 to 20 carbons, or a foregoing U′ group substituted with apentafluorophenyl ester group. Each U″ group independently represents analkyl group comprising 1 to 20 carbons or an aryl group comprising 1 to20 carbons, or a foregoing U″ group substituted with a pentafluorophenylester group. In an embodiment, none of the U′ or U″ groups comprise apentafluorophenyl ester group. In another embodiment, the U′ groupattached to the carbon labeled 5 in formula (6) is ethyl or methyl, andall other U′ groups are hydrogen. In an embodiment, the U′ groupattached to carbon labeled 5 in formula (6) is ethyl or methyl, carbonlabeled 5 in formula (6) is an asymmetric center, and the cycliccarbonyl compound comprises the (R) or (S) isomer in greater than 80%enantiomeric excess.

As one example, the preparation of first cyclic monomer MTC-PhF₅, (7),from the biocompatible precursor compound, bis(2,2-methylol) propionicacid (bis-MPA), (8), is illustrated in Scheme 2.

Bis-MPA is converted to MTC-PhF₅ in one step under mild conditions.MTC-PhF₅ has an active pentafluorophenyl ester (PFP ester) and a methylgroup attached to the 5-position of the trimethylene carbonate ring. Thereaction can be conducted with about 2 to about 2.5 molar equivalents ofPFC, more specifically 2.01 to 2.1 molar equivalents, based on moles ofbis-MPA. Generally, 1 mole of pentafluorophenol is consumed to form thePFP ester and 3 moles of pentafluorophenol are produced as a byproduct(not shown) per 2 moles of PFC used. Each theoretical mole ofpentafluorophenol byproduct can be recovered in 90% to 100% yield forrecycling back to PFC. In an embodiment, the theoretical amount ofpentafluorophenol byproduct is quantitatively recovered for recyclingback to PFC. MTC-PhF₅ is a white, crystalline powder which can be easilyhandled, manipulated, stored, and shipped, unlike an acylchloride-functionalized cyclic carbonate.

Also contemplated is the reaction of a carboxy-substituted diamine withPFC to form a cyclic urea comprising an active pentafluorophenyl estergroup, the reaction of a carboxy-substituted amino-alcohol with PFC toproduce a cyclic carbamate comprising a pentafluorophenyl ester group,the reaction of a carboxy-substituted mercapto-alcohol with PFC toproduce a cyclic thiocarbonate comprising a pentafluorophenyl estergroup, the reaction of a carboxy-substituted amine-thiol with PFC toproduce a cyclic thiocarbamate comprising a pentafluorophenyl estergroup, and the reaction of a carboxy-substituted dithiol with PFC toproduce a cyclic dithiocarbonate comprising a pentafluorophenyl estergroup.

Another challenge in preparing cyclic monomers, for example cycliccarbonates from 1,3-diols, is achieving selective ring closure withoutpolymerization, which depends on the nucleophilicity of the leavinggroup and the catalyst used. Advantageously, the pentafluorophenolbyproduct is a weak nucleophile and does not initiate polymerization. Inan embodiment, the disclosed method produces more than 0 to less than0.5 wt. % of a polymer byproduct derived from the precursor compound,based on the weight of the precursor compound. In another embodiment,the disclosed method produces no detectable polymer byproduct derivedfrom the precursor compound.

The first mixture comprises a catalyst suitably chosen to activate thenucleophilic diol, diamine, amino-alcohol, mercapto-alcohol,amino-thiol, or dithiol functional groups and not the electrophilic PFCcarbonyl group. Exemplary catalysts include tertiary amines, for example1,8-bis(dimethylamino)naphthalene, referred to also as PROTON SPONGE, atrademark of Sigma-Aldrich. Still other catalysts include halide saltsof Group I elements, particularly lithium (Li), sodium (Na), potassium(K), rubidium (Rb), cesium (Cs), or francium (Fr). In one embodiment thecatalyst is CsF.

The catalyst can be present in an amount of 0.02 to 1.00 moles per moleof the precursor compound, more particularly 0.05 to 0.50 moles per moleof the precursor compound, and even more particularly 0.15 to 0.25 molesper mole of the precursor compound.

The first mixture optionally includes a solvent such as tetrahydrofuran,methylene chloride, chloroform, acetone, methyl ethyl ketone,acetonitrile, ethyl acetate, butyl acetate, benzene, toluene, xylene,hexane, petroleum ethers, 1,4-dioxane, diethyl ether, ethylene glycoldimethyl ether, or combinations thereof. When a solvent is present, theconcentration of precursor compound in the solvent can be from about0.01 to about 10 moles per liter, more typically about 0.02 to 0.8 molesper liter, more specifically 0.1 to 0.6 moles per liter, or mostspecifically 0.15 to 0.25 moles per liter. In one embodiment, thereaction mixture consists of the precursor compound, PFC, a catalyst anda solvent. In one embodiment the solvent is anhydrous.

The method (Method 1) includes agitating the first mixture at atemperature suitable for converting the precursor compound to the firstcyclic monomer. The temperature can be from −20° C. to 100° C., 0° C. to80° C., 10° C. to 50° C., or more specifically ambient or roomtemperature, typically 17° C. to 30° C. Optionally, the reaction mixtureis agitated under an inert atmosphere. In one embodiment, thetemperature is ambient temperature.

Agitation of the first mixture can be conducted for 1 hour to 120 hours,5 hours to 48 hours, and more specifically 12 hours to 36 hours. In oneembodiment, agitation is conducted for 15 to 24 hours at ambienttemperature.

The second mixture comprises the first cyclic carbonyl monomercomprising the pentafluorophenyl ester and pentafluorophenol byproduct.The cyclic monomer can be isolated using any known method ofpurification, including distillation, chromatography, extraction, andprecipitation. In one embodiment, the cyclic monomer is purified byselective precipitation of the pentafluorophenol byproduct or the cyclicmonomer from the second mixture. In one variation on selectiveprecipitation, the reaction mixture comprises a first solvent in whichthe precursor compound, PFC, cyclic monomer and pentafluorophenolbyproduct are highly soluble. Upon completion of the reaction to formthe cyclic monomer, the first solvent is removed by, for example, vacuumdistillation, followed by addition of a second solvent suitably chosento selectively precipitate the pentafluorophenol byproduct or the cyclicmonomer. In another variation, the first solvent can be selected tofacilitate precipitation of the cyclic monomer or the pentafluorophenolbyproduct from the second mixture as the reaction proceeds.

The method can further comprise the step of recovering thepentafluorophenol byproduct for recycling. For reactions in which onemole of pentafluorophenol is consumed in making the pentafluorophenylester, the yield of recovered pentafluorophenol byproduct from thesecond mixture is about 80% to 100%, more specifically 90% to 100%,based on the theoretical amount of pentafluorophenol byproduct formed.In an embodiment, the theoretical amount of pentafluorophenol byproductis quantitatively recovered for recycling back to PFC.

Method 2. Functionalization of the First Cyclic Monomer.

Also disclosed is a mild method (Method 2) of deriving a second cycliccarbonyl monomer from the first cyclic carbonyl monomer, by convertingthe pentafluorophenyl ester (PFP ester) into a different ester, anamide, or a thioester, without altering the cyclic carbonyl moiety ofthe first cyclic carbonyl monomer. Typically, a catalyst is also used inMethod 2, although it is not required, such as in the reaction of a PFPester with a primary amine (Example 3).

More specifically, a method of deriving a second cyclic carbonyl monomerfrom the first cyclic carbonyl monomer comprises forming a first mixturecomprising a first cyclic carbonyl monomer (e.g., MTC-PhF₅) comprising apentafluorophenyl ester group and a cyclic carbonyl group selected fromcyclic carbonate, cyclic carbamate, cyclic urea, cyclic thiocarbonate,cyclic thiocarbamate, cyclic dithiocarbonate, and combinations thereof;an optional solvent; an optional catalyst; and a nucleophile comprising1 to 30 carbons comprising an alcohol other than pentafluorophenol, anamine, a thiol, or combinations thereof; and agitating the first mixtureto form a second mixture comprising the second cyclic carbonyl monomerand a pentafluorophenol byproduct. The second cyclic carbonyl monomercomprises an ester, an amide, or a thioester group derived from thepentafluorophenyl ester. In an embodiment, the first cyclic carbonylmonomer has the general formula (4) as described above. In anotherembodiment, the first cyclic monomer has the general formula (6), asdescribed above. In another embodiment, the first cyclic monomercomprises a single pentafluorophenyl ester group.

In an even more specific embodiment, the first cyclic monomer isMTC-PhF₅. As an example, MTC-PhF₅ can be converted to the corresponding2,2,2-trifluoroethyl ester, MTC-TFE, (22), according to Scheme 3.

Non-limiting examples of other alcohols capable of transesterifying thePFP ester of MTC-PhF₅ without altering the cyclic carbonate groupinclude:

Non-limiting examples of amines capable of reacting with the PFP esterof MTC-PhF₅ to form an amide without altering the cyclic carbonate groupinclude:

dimethylamine, andisopropylamine.

Non-limiting examples of thiols capable of reacting with the PFP esterto form a thioester without altering the cyclic carbonyl group include:(see Part II)

The alcohol, amine, thiol or combinations thereof may be attached tolarger structures including oligomers, polymers, biomacromolecules,particles, and functionalized surfaces, Non-limiting polymeric scaffoldsinclude linear, branched, hyperbranched, cyclic, dendrimeric, block,graft, star, and other known polymer structures. Non-limitingbiomacromolecules include proteins, DNA, RNA, lipids, phospholipids.Non-limiting particles may have dimensions ranging from less than 1nanometer to hundreds of micrometers. Non-limiting large particlesinclude silica, alumina, and polymeric resins such as those commonlyused for chromatography and functionalized polymeric beads such as thosecommonly used for solid-phase synthesis. Non-limiting nanoparticlesinclude both organic and inorganic nanoparticles including thosefunctionalized with ligands or stabilizing polymers. Non-limitingorganic nanoparticles may include crosslinked polymeric nanoparticles,dendrimers, and star polymers. Non-limiting inorganic nanoparticlesinclude metallic nanoparticles (e.g., gold, silver, other transitionmetals, and Group 13 to Group 16 metals of the periodic table), oxidenanoparticles (e.g., alumina, silica, hafnia, zirconia, zinc oxide),nitride nanoparticles (e.g., titanium nitride, gallium nitride), sulfidenanoparticles (e.g., zinc sulfide) semiconducting nanoparticles (e.g.,cadmium selenide). Non-limiting functionalized surfaces include surfacesfunctionalized with self-assembled monolayers.

Generally, the first mixture of Method 2 is agitated at a temperature of−78° C. to 100° C., more specifically −20° C. to 50° C., and even morespecifically −10° C. to 30° C. to form the second cyclic monomer. In anembodiment, agitation to convert the PFP ester to a different ester,amide or thiol is conducted at ambient temperature, or 17° C. to 30° C.The first mixture is agitated for a period of about 1 hour to about 48hours, more particularly about 20 to 30 hours at the reactiontemperature.

Typically, a solvent is used in Method 2, though not required. Dependingon the solvent, the pentafluorophenol byproduct can in some instancesprecipitate directly from the reaction mixture as it is formed.Generally, however, the second mixture is concentrated under vacuum andthe resulting residue is then treated with a second solvent in which thepentafluorophenol byproduct is not soluble, such as methylene chloride.The pentafluorophenol byproduct can then be filtered and recovered forrecycling back to PFC. In an embodiment, 90% to 100% of the theoreticalpentafluorophenol byproduct is recovered for recycling back to PFC. Thederived second cyclic monomer can be isolated by washing the organicfiltrate with a base such as sodium bicarbonate solution, drying thefiltrate with a drying agent such as magnesium sulfate, and evaporationof the second solvent under vacuum. In this manner the second cyclicmonomer can be obtained in a yield of about 50% to about 100%, moreparticularly about 70% to 100%, even more particularly about 80% to100%.

The optional catalyst of Method 2 can be selected from typical catalystsfor transesterifications, conversions of esters to amides, or conversionof esters to thioesters. These include organic catalysts and inorganiccatalysts, in particular the above described catalysts, and mostspecifically cesium fluoride. When used in Method 2, the catalyst can bepresent in an amount of 0.02 to 1.00 moles per mole of the first cyclicmonomer, more particularly 0.05 to 0.50 moles per mole of the firstcyclic monomer, and even more particularly 0.15 to 0.25 moles per moleof the first cyclic monomer.

In an additional embodiment, the Methods 1 and 2 are performed step-wisein a single reaction vessel, without an intermediate step to isolate thefirst cyclic carbonyl monomer.

The above-described methods provide a controlled process for introducinga wide range of functionality and connectivity into cyclic monomers forring-opening polymerizations. As stated above, the cyclic monomers(first and/or second cyclic monomers) can be formed in isomerically pureform, or as racemic mixtures.

Method 3. Ring Opening Polymerization of the First Cyclic Monomer.

Further disclosed are polymers obtained by ring opening polymerizationof the above described cyclic monomers, including the first and secondcyclic monomers. The following description of ROP methods applies to allcyclic monomers described herein.

The above-described cyclic monomers can undergo ring-openingpolymerization (ROP) to form biodegradable polymers of differenttacticities. Atactic, syndiotactic and isotactic forms of the polymerscan be produced that depend on the cyclic monomer(s), its isomericpurity, and the polymerization conditions.

A method (Method 3) of ring-opening polymerization comprises forming afirst mixture comprising the cyclic monomer, a catalyst, an initiator,and an optional solvent. The first mixture is then heated and agitatedto effect polymerization of the cyclic monomer, forming a second mixturecontaining the biodegradable polymer product.

The ring opening polymerization is generally conducted in a reactorunder inert atmosphere such as nitrogen or argon. The polymerization canbe performed by solution polymerization in an inactive solvent such asbenzene, toluene, xylene, cyclohexane, n-hexane, dioxane, chloroform anddichloroethane, or by bulk polymerization. The ROP reaction temperaturecan be from 20° to 250° C. Generally, the reaction mixture is heated atatmospheric pressure for 0.5 to 72 hours to effect polymerization.Subsequently, additional cyclic monomer and catalyst can be added to thesecond mixture to effect block polymerization if desired.

Exemplary ROP catalysts include tetramethoxy zirconium,tetra-iso-propoxy zirconium, tetra-iso-butoxy zirconium, tetra-n-butoxyzirconium, tetra-t-butoxy zirconium, triethoxy aluminum, tri-n-propoxyaluminum, tri-iso-propoxy aluminum, tri-n-butoxy aluminum,tri-iso-butoxy aluminum, tri-sec-butoxy aluminum,mono-sec-butoxy-di-iso-propoxy aluminum, ethyl acetoacetate aluminumdiisopropylate, aluminum tris(ethyl acetoacetate), tetraethoxy titanium,tetra-iso-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxytitanium, tetra-sec-butoxy titanium, tetra-t-butoxy titanium,tri-iso-propoxy gallium, tri-iso-propoxy antimony, tri-iso-butoxyantimony, trimethoxy boron, triethoxy boron, tri-iso-propoxy boron,tri-n-propoxy boron, tri-iso-butoxy boron, tri-n-butoxy boron,tri-sec-butoxy boron, tri-t-butoxy boron, tri-iso-propoxy gallium,tetramethoxy germanium, tetraethoxy germanium, tetra-iso-propoxygermanium, tetra-n-propoxy germanium, tetra-iso-butoxy germanium,tetra-n-butoxy germanium, tetra-sec-butoxy germanium and tetra-t-butoxygermanium; halogenated compound such as antimony pentachloride, zincchloride, lithium bromide, tin(IV) chloride, cadmium chloride and borontrifluoride diethyl ether; alkyl aluminum such as trimethyl aluminum,triethyl aluminum, diethyl aluminum chloride, ethyl aluminum dichlorideand tri-iso-butyl aluminum; alkyl zinc such as dimethyl zinc, diethylzinc and diisopropyl zinc; tertiary amines such as triallylamine,triethylamine, tri-n-octylamine and benzyldimethylamine; heteropolyacidssuch as phosphotungstic acid, phosphomolybdic acid, silicotungstic acidand alkali metal salt thereof; zirconium compounds such as zirconiumacid chloride, zirconium octanoate, zirconium stearate and zirconiumnitrate. More particularly, the catalyst is zirconium octanoate,tetraalkoxy zirconium or a trialkoxy aluminum compound.

Other ROP catalysts include metal-free organocatalysts that can providea platform to polymers having controlled, predictable molecular weightsand narrow polydispersities. Examples of organocatalysts for the ROP ofcyclic esters, carbonates and siloxanes are 4-dimethylaminopyridine,phosphines, N-heterocyclic carbenes (NHC), bifunctional aminothioureas,phosphazenes, amidines, and guanidines.

The ROP reaction mixture comprises at least one catalyst and, whenappropriate, several catalysts together. The ROP catalyst is added in aproportion of 1/20 to 1/40,000 moles relative to the cyclic monomers,and preferably of 1/1,000 to 1/20,000 moles.

The ROP reaction mixture also comprises an initiator. Initiatorsgenerally include nucleophiles such as alcohols, amines and thiols. Theinitiator can be monofunctional, difunctional or multifunctional such asdendritic, polymeric or related architectures. Monofunctional initiatorscan include nucleophiles with protected functional groups that includethiols, amines, acids and alcohols. A typical initiator is phenol orbenzyl alcohol.

Well-known apparatuses can be used for performing the ROPpolymerization. Examples of tower type reaction apparatus include areaction vessel comprising helical ribbon wings and transformationalspiral baffles. Examples of sideways type reaction apparatus include asideways type one- or twin-shaft kneader comprising agitation shaftswhich have a row of transformational wings and arranged in parallel toeach other. In addition, the reaction apparatus may be either a batchtype or a continuous one. Examples of the batch type apparatus includeMax Blend Type Reactor (made by Sumitomo Heavy Machine Co., Ltd.), SuperBlend Type Reactor (made by Sumitomo Heavy Machine Co., Ltd.),ReverseCone Ribbon Wing Type Reactor (made by Mitsubishi HeavyIndustries Co., Ltd.), Spiral Lattice-Shaped Wing Type Reactor (HitachiSeisakusho Co., Ltd.). Examples of the continuous type apparatus includeBIVOLAK (made by Sumitomo Heavy Machine Co., Ltd.), HitachiSpectacles-Shaped Polymerization Machine (made by Hitachi SeisakushoCo., Ltd.), Hitachi Lattice-Shaped Polymerization Machine (made byHitachi Seisakusho Co., Ltd.), Self-Cleaning Type Reactor (made byMitsubishi Heavy Industries Co., Ltd.), Twin-Shaft Sideways Type Reactor(made by Mitsubishi Heavy Industries Co., Ltd.), KRC Kneader (made byKurimoto Co., Ltd.), TEX-K (The Japan Steel Work Co., Ltd.) and single-or twin-screw extruders widely used for extrusion molding of plasticsand devolatilization treatment.

The biodegradeable ROP product can be a homopolymer, copolymer, or blockcopolymer. The biodegradable polymer can have a number-average molecularweight of usually 1,000 to 200,000, more particularly 2,000 to 100,000,and still more particularly 5,000 to 80,000.

The biodegradable polymer product of the ROP polymerization can beapplied to conventional molding methods such as compression molding,extrusion molding, injection molding, hollow molding and vacuum molding,and can be converted to molded articles such as various parts,receptacles, materials, tools, films, sheets and fibers. A moldingcomposition can be prepared comprising the biodegradable polymer andvarious additives, including for example nucleating agents, pigments,dyes, heat-resisting agents, antioxidants, weather-resisting agents,lubricants, antistatic agents, stabilizers, fillers, strengthenedmaterials, fire retardants, plasticizers, and other polymers. Generally,the molding compositions comprise 30 wt. % to 100 wt. % or more of thebiodegradable polymer based on total weight of the molding composition.More particularly, the molding composition comprises 50 wt. % to 100 wt.% of the biodegradable polymer.

The biodegradable polymer product of the ROP polymerization can beformed into free-standing or supported films by known methods.Non-limiting methods to form supported films include dip coating, spincoating, spray coating, doctor blading. Generally, such coatingcompositions comprise 0.01 wt. % to 90 wt. % of the biodegradablepolymer based on total weight of the coating composition. Moreparticularly, the molding composition comprises 1 wt. % to 50 wt. % ofthe biodegradable polymer based on total weight of the coatingcomposition. The coating compositions generally also include a suitablesolvent necessary to dissolve the biodegradable polymer product.

The coating compositions can further include other additives selected soas to optimize desirable properties, such as optical, mechanical, and/oraging properties of the films. Non-limiting examples of additivesinclude surfactants, ultraviolet light absorbing dyes, heat stabilizers,visible light absorbing dyes, quenchers, particulate fillers, and flameretardants. Combinations of additives can also be employed.

The following Example 1 illustrates the method of making a first cycliccarbonyl monomer, MTC-PhF₅. Examples 2-15 illustrate Method 2,displacing the PFP ester of MTC-PhF₅ to form a variety of second cyclicmonomers comprising different ester or amide groups.

EXAMPLES Example 1 Preparation of5-methyl-5-pentafluorophenyloxycarboxyl-1,3-dioxane-2-one, MTC-PhF₅, (7)

A 100 mL round bottom flask was charged with bis-MPA, (7), (5.00 g, 37mmol), bis-(pentafluorophenol) carbonate (PFC, 31.00 g, 78 mmol), andCsF (2.5 g, 16.4 mmol rinsed in with 70 mis of tetrahydrofuran (THF).Initially the reaction was heterogeneous, but after one hour a clearhomogeneous solution was formed that was allowed to stir for 20 hours.The solvent was removed in vacuo and the residue was re-dissolved inmethylene chloride. The solution was allowed to stand for approximately10 minutes, at which time the pentafluorophenol byproduct precipitatedand could be quantitatively recovered. This pentafluorophenol byproductshowed the characteristic 3 peaks in the ¹⁹F NMR of pentafluorophenoland a single peak in the GCMS with a mass of 184. The filtrate wasextracted with sodium bicarbonate, water and was dried with MgSO₄. Thesolvent was evaporated in vacuo and the product was recrystallized(ethylacetate/hexane mixture) to give MTC-PhF₅, (8), as a whitecrystalline powder (GCMS single peak with mass of 326 g/mol, calculatedmolecular weight for C₁₂H₇F₅O₅ (326 g/mol) consistent with the assignedstructure. FIG. 1 shows ¹H NMR and ¹⁹F NMR spectrographs of MTC-PhF₅.¹H-NMR (400 MHz in CDCl₃): δ 4.85 (d, J=10.8 Hz, 2H, CH_(a)H_(b)), 4.85(d, J=10.8 Hz, 2H, CH_(a)H_(b)), 1.55 (s, 3H, CCH₃).

Example 2 Preparation of MTC-Et, (9)

A round bottom flask was charged with a THF solution of MTC-PhF₅,ethanol and CsF. The reaction was allowed to stir overnight, after whichNMR analysis on the crude product showed about 95% conversion to theethyl ester carbonate. The solvent was removed and the mixture wasre-dissolved in methylene chloride. The solution was allowed to standfor approximately 10 min, at which time the pentafluorophenol byproductprecipitated and could be quantitatively recovered. This byproductshowed the characteristic 3 peaks in the ¹⁹F NMR of pentafluorophenoland a single peak in the GCMS with a mass of 184 g/mol. The organicphase was treated with saturated NaHCO₃ (200 mL), brine (200 mL), andwater (200 mL), and dried over MgSO₄. The solvent was evaporated invacuo, and the residue was recrystallized from ethyl acetate to givewhite crystals (56% yield). GCMS showed a single peak with mass of 189g/mol, calculated molecular weight for C₈H₁₂O₅ (188 g/mol) consistentwith the assigned structure (FIG. 2). ¹H NMR: δ 4.68 (d, 2H, CH₂OCOO),4.25 (q, 1H, OCH₂CH₃), 4.19 (d, 2H, CH₂OCOO), 1.32 (s, 3H, CH₃), 1.29(t, 3H, CH₃CH₂O). ¹³C NMR: δ 171.0, 147.5, 72.9, 62.1, 39.9, 17.3, 13.8.

Example 3 Preparation of MTC-BnAmine, (10)

To a THF solution of bis-MPA carbonate (0.25 g, 0.76 mmol), benzyl amine(0.08 g, 0.76 mmol) dissolved in THF was added dropwise at 0° C. ¹H NMRafter 5 minutes reaction time showed 60% conversion at 0° C. Thereaction was allowed to proceed overnight and slowly warm to roomtemperature. The ¹H NMR of the reaction mixture showed quantitativeconversion of the ester to the amide with no residual benzyl amine andno side reactions. The reaction mixture was concentrated and dissolvedin methylene chloride, a non-solvent for the pentafluorophenol, whichwas filtered. The product was concentrated and crystallized from ethylacetate/hexane mixtures. Yield: 70%. GCMS showed a single peak with massof 249 g/mol, calculated molecular weight for C₁₃H₁₅NO₅ (249 g/mol)consistent with the assigned structure (FIG. 3). ¹H-NMR (400 MHz inCDCl₃): δ 7.30-7.45 (m, 5H, ArH), 4.70 (d, J=10.8 Hz, 2H, CH_(a)H_(b)),4.50 (d, 2H, ArCH₂N), 1.35 (s, 3H, CCH₃).

Example 4 Preparation of MTC-OCH₂CCH, (11)

A round bottom flask was charged with MTC-PhF₅ (0.70 g, 0.0021 mol), CsF(0.10 g, 0.66 mmol) and propargyl alcohol (0.29 g, 0.0021 mol), rinsedin with 10 mL of THF. The mixture was stirred for 24 hours at ambienttemperature, filtered to remove pentafluorophenol, and the solvent wasevaporated in vacuo. The reaction mixture was dissolved in methylenechloride, allowed to stand for about 30 min, and filtered to removeadditional pentafluorophenol byproduct that was quantitativelyrecovered. This byproduct showed the characteristic 3 peaks in the ¹⁹FNMR of pentafluorophenol and a single peak in the GCMS with a mass of184 g/mol. The organic phase was then treated with saturated NaHCO₃ (200mL), brine (200 mL), water (200 mL), dried over MgSO₄ and wasconcentrated. The crude product was purified by column chromatography(silica, 1:1 ethyl acetate/hexanes) to a clear oil that slowlysolidified to a white solid, m.p. 70 to 72° C. Yield: (65%). GCMS showeda single peak with mass of 198 g/mol, calculated molecular weight forC₉H₁₀O₅ (198 g/mol) consistent with the assigned structure (FIG. 4).¹H-NMR: δ 4.80 (d, J=2.4 Hz, 2H, OCH₂CCH), 4.72 (d, J=10.8 Hz, 2H,CH_(a)H_(b)), 4.24 (d, J=10.8 Hz, 2H, CH_(a)H_(b)), 2.55 (t, J=2.4 Hz,1H, OCH₂CCH), 1.38 (s, 3H, CCH₃). ¹³C-NMR: δ 170.8, 147.7, 76.8, 76.4,73.2, 53.9, 40.6, 17.8.

Example 5 Preparation of MTC-OCH₂CH₂CH₂Br, (12)

A round bottom flask was charged with MTC-PhF₅ (0.7 g, 0.0021 mol), CsF(0.10 g, 0.66 mmol) and 3-bromopropanol (0.298 g, 0.0021 mol), rinsed inwith 10 mL of THF. The reaction mixture was stirred for 24 hours,filtered to remove pentafluorophenol byproduct, and the solvent wasevaporated in vacuo. The reaction mixture was dissolved in methylenechloride, allowed to stand for about 30 min, and filtered to remove moreprecipitated pentafluorophenol by-product. The pentafluorophenolbyproduct was quantitatively recovered. This byproduct showed thecharacteristic 3 peaks in the ¹⁹F NMR of pentafluorophenol and a singlepeak in the GCMS with a mass of 184 g/mol. The organic phase was thentreated with saturated NaHCO₃ (200 mL), brine (200 mL), water (200 mL),dried over MgSO₄ and concentrated. The crude product was purified bycolumn chromatography (silica, 1:1 ethyl acetate/hexanes) to a clear,colorless oil. Yield: 70%. GCMS showed a single peak with mass of 281g/mol, calculated molecular weight for C₉H₁₃O₅ (280 g/mol) consistentwith the assigned structure (FIG. 5). ¹H-NMR: δ 4.70 (d, J=10.8 Hz, 2H,CH_(a)H_(b)), 4.40 (t, J=6.0 Hz, 2H, OCH₂CH₂), 4.22 (d, J=10.8 Hz, 2H,CH_(a)H_(b)), 3.50 (t, J=6.0 Hz, 2H, CH₂Cl), 2.08 (quip, J=6.0 Hz, 2H,CH₂CH₂CH₂), 1.27 (s, 3H, CCH₃).

Example 6 Preparation of MTC-OCH₂CHCH₂, (13)

A round bottom flask was charged with MTC-PhF₅ (1.18 g, 0.0036 mol), CsF(0.35 g, 0.0023 mol) and allyl alcohol (0.219 g, 0.00037 mol), rinsed inwith 10 mL of THF. The mixture was stirred for 24 hours, filtered toremove pentafluorophenol byproduct, and the solvent was evaporated invacuo. The crude product was dissolved in methylene chloride, and thesolution was allowed to stand for about 30 min, during which time morepentafluorophenol byproduct precipitated. The pentafluorophenolbyproduct was filtered, and was quantitatively recovered. The byproductshowed the characteristic 3 peaks in the ¹⁹F NMR of pentafluorophenoland a single peak in the GCMS with a mass of 184 g/mol. The organicphase was treated sequentially with saturated NaHCO₃ (200 mL), brine(200 mL), and water (200 mL), then dried over MgSO₄ and concentrated.Purification of the product by column chromatography (silica, 1:1 ethylacetate/hexanes) provided the desired material as an oil that slowlysolidified to a white solid, m.p. 64° C. to 66° C. Yield: 65%. GCMSshowed a single peak with mass of 201 g/mol, calculated molecular weightfor C₉H₁₂O₅ (200 g/mol) consistent with the assigned structure (FIG. 6).¹H-NMR: δ 5.80-5.90 (m, 1H CH), 4.65 (t, 2H, COOCH₂), 4.60 (d, J=10.8Hz, 2H, CH_(a)H_(b)), 4.24 (d, J=10.8 Hz, 2H, CH_(a)H_(b)), 1.38 (s, 3H,CCH₃).

Example 7 Preparation of MTC-OCH₂CH₂SS(2-Py), (14)

A round bottom flask was charged with MTC-PhF₅ (0.25 g, 0.0007 mol), CsF(0.05 g, 0.33 mmol) and S-2-pyridyl-S′-2-hydroxyethyl disulfide (0.15 g,0.0008 mol), rinsed in with 10 mL of THF. The mixture was stirred for 24hours and filtered to remove pentafluorophenol byproduct. The solventwas then evaporated in vacuo. The reaction mixture was dissolved inmethylene chloride, allowed to stand about 30 minutes, and additionalprecipitated pentafluorophenol byproduct was filtered. Thepentafluorophenol byproduct was quantitatively recovered. This byproductshowed the characteristic 3 peaks in the ¹⁹F NMR of pentafluorophenoland a single peak in the GCMS with a mass of 184 g/mol. The organicphase was treated with saturated NaHCO₃ (200 mL), brine (200 mL), water(200 mL), dried over MgSO₄ and concentrated. The crude product waspurified by column chromatography (silica, 1:1 ethyl acetate/hexanes) toan oil that slowly solidified to a white solid, mp 64-65° C. Yield: 65%.GCMS showed a single peak with mass of 220 g/mol, consistent with theloss of pyridyl thione, calculated molecular weight for C₁₃H₁₅NO₅S₂ (329g/mol) consistent with the assigned structure (FIG. 7). ¹H-NMR: δ 8.49(m, 1H, ArH), 7.67 (m, 2H, ArH), 7.14 (m, 1H, ArH), 4.70 (d, J=10.8 Hz,2H, CH_(a)H_(b)), 4.49 (t, J=6.4 Hz, 2H, COOCH₂), 4.21 (d, J=10.8 Hz,2H, CH_(a)H_(b)), 3.08 (t, J=6.4 Hz, 2H, SCH₂), 1.35 (s, 3H, CCH₃).¹³C-NMR: δ 171.3, 159.5, 150.2, 147.8, 137.6, 121.5, 120.4, 73.3, 64.1,40.7, 37.3, 18.0.

Example 8 Preparation of MTC-OCH₂CH₂OTHP, (15)

A round bottom flask was charged with MTC-PhF₅ (0.95, 0.0028 mol), CsF(0.14 g, 0.92 mmol) and 2-(tetrahydro-2H-pyran-2-yloxy)ethanol (0.43 g,0.0029 mol), rinsed in with 10 mL of THF. The mixture was stirred for 24hours, filtered to remove pentafluorophenol byproduct, and the solventwas evaporated. The reaction mixture was dissolved in methylenechloride, allowed to stand for about 30 min, and the additionalprecipitated pentafluorophenol byproduct was filtered. Thepentafluorophenol byproduct was quantitatively recovered. This byproductshowed the characteristic 3 peaks in the ¹⁹F NMR of pentafluorophenoland a single peak in the GCMS with a mass of 184 g/mol. The organicphase was then treated with saturated NaHCO₃ (200 mL), brine (200 mL),water (200 mL), and dried over MgSO₄. The solvent was removed in vacuo.The crude product was purified by column chromatography (silica, 1:1ethyl acetate/hexanes) to a colorless oil (Yield: 65%). GCMS showed asingle peak with mass of 287 g/mol, calculated molecular weight forC₁₃H₂₀O₅ (288 g/mol) consistent with the assigned structure (FIG. 8). ¹HNMR: δ 4.70 (d, 2H, CH₂OCOO), 4.61 (t, 1H, OCHO), 4.38 (m, 2H,OCOCH₂CH₂), 4.20 (d, 2H, CH₂OCOO), 3.92 (m, 1H, CH_(a)H_(b)OCH), 3.82(m, 1H, OCH_(a)H_(b)CH₂CH₂), 3.65 (m, 1H, CH_(a)H_(b)OCH), 3.51 (m, 1H,OCH_(a)H_(b)CH₂CH₂), 1.85-1.65 (m, 2H, CHCH₂), 1.61-1.47 (m, 4H,CH₂CH₂CH₂CH₂), 1.35 (s, 3H, CH₃). ¹³C NMR: d 170.9, 147.4, 98.7, 72.9,65.0, 64.7, 62.1, 40.1, 30.3, 25.2, 19.2, 17.5.

Example 9 Preparation of MTC-OCH₂CH₂NHBoc, (16)

A round bottom flask was charged with MTC-PhF₅ (0.86, 0.00265 mol), CsF(0.14 g, 0.92 mmol) and N-Boc-ethanolamine (0.43 g, 0.0027 mol), rinsedin with 10 mL of THF. The reaction mixture was stirred for 24 hours,filtered to remove pentafluorophenol byproduct, and the solvent wasevaporated in vacuo. The reaction mixture was redissolved in methylenechloride. After about 30 minutes, more of the pentafluorophenolbyproduct precipitated and was filtered. The pentafluorophenol byproductwas quantitatively recovered. This byproduct showed the characteristic 3peaks in the ¹⁹F NMR of pentafluorophenol and a single peak in the GCMSwith a mass of 184 g/mol. The organic phase was then treated withsaturated NaHCO₃ (200 mL), brine (200 mL), water (200 mL), dried overMgSO₄ and concentrated. Purification of the crude product by columnchromatography (silica, 1:1 ethyl acetate/hexanes) provided the productas a solid, m.p. 52° C. to 55° C. Yield: 65%. GCMS showed a single peakwith mass of 204 g/mol, with the loss of the boc-protecting group,calculated molecular weight for C₁₃H₁₅NO₇ (303 g/mol) consistent withthe assigned structure (FIG. 9). ¹H-NMR: δ 4.88 (br, 1H, NH), 4.69 (d,J=10.8 Hz, 2H, Cl/Ji_(b)), 4.26 (t, J=5.2 Hz, 2H, OCH₂CH₂), 4.21 (d,J=10.8 Hz, 2H, CH_(a)H_(b)), 3.42 (m, 2H, CH₂CH₂NH), 1.44 (s, 9H,C(CH₃)₃), 1.34 (s, 3H, CCH₃). ¹³C-NMR: δ 171.5, 156.3, 148.0, 80.1,73.4, 65.8, 40.6, 39.8, 28.7, 17.8.

Example 10 Preparation of MTC-OBn, (17)

A round bottom flask was charged with MTC-PhF₅ (0.50, 0.0015 mol), CsF(0.30 g, 0.002 mol) and benzyl alcohol (0.17 g, 0.0015 mol), rinsed inwith 10 mL of THF. The reaction mixture was stirred for 24 hours,filtered to remove pentafluorophenol byproduct, and the solvent wasevaporated in vacuo. The reaction mixture was dissolved in methylenechloride. After about 30 minutes, more of the pentafluorophenolbyproduct had precipitated and was filtered. The pentafluorophenolbyproduct was quantitatively recovered. This byproduct showed thecharacteristic 3 peaks in the ¹⁹F NMR of pentafluorophenol and a singlepeak in the GCMS with a mass of 184 g/mol. The organic phase was thentreated with saturated NaHCO₃ (200 mL), brine (200 mL), water (200 mL),dried over MgSO₄, and concentrated in vacu. The crude product waspurified by column chromatography (silica, 1:1 ethyl acetate/hexanes) togive a solid, m.p. 67° C. to 69° C. Yield: 68%. GCMS showed a singlepeak with mass of 250 g/mol, calculated molecular weight for C₁₃H₁₄O₅(250 g/mol) consistent with the assigned structure (FIG. 10). ¹H-NMR(400 MHz in CDCl₃): δ 7.45 (m, 5H, ArH), 5.3 (s, 2H, ArCH₂), 4.70 (d,J=10.8 Hz, 2H, CH_(a)H_(b)), 4.25 (d, J=10.8 Hz, 2H, CH_(a)H_(b)), 1.35(s, 3H, CCH₃).

Example 11 Preparation of MTC-OCH₂CH₂OCH₂CH₂OMe, (18)

A round bottom flask was charged with MTC-PhF₅ (0.86, 0.00265 mol), CsF(0.14 g, 0.92 mmol) and diethylene glycol monomethyl ether (0.43 g,0.0027 mol), rinsed in with 10 mL of THF. The reaction mixture wasstirred for 24 hours, filtered to remove pentafluorophenol byproduct,and the solvent was evaporated in vacuo. The residue was dissolved inmethylene chloride, allowed to stand about 30 minutes, and theadditional precipitated pentafluorophenol byproduct was filtered. Thepentafluorophenol byproduct was quantitatively recovered. The filtratewas concentrated and then dissolved in diethyl ether. The productseparated out of the diethyl ether and was removed in a separationfunnel and used without further purification (FIG. 11). The product wasisolated as a liquid. Yield: about 50%. ¹H-NMR (400 MHz in CDCl₃):δ=4.73-4.70 (d, 2H, —CH₂OCOOCH₂CCH₃—), 4.38-4.36 (t, 2H,PEG-CH₂CH₂—OCO), 4.22-4.20 (d, 4H, —CH₂OCOOCH₂CCH₃—), 3.65 (m, 4H,OCH2CH2 PEG), 3.38 (s, 3H, OCH2CH2OCH3 PEG), 1.38 (s, 3H,CCH₃CH₂CCOOCH₂).

Example 12 Preparation of MTC-dinitroPHS, (19)

A round bottom flask was charged with MTC-PhF₅ (2.40 g, 7.43 mmol), CsF(0.31 g, 2.04 mmol) and 2-(2,4-dinitrophenylthio)ethanol (2.00 g, 8.19mmol), rinsed in with 35 mL of THF. The mixture was stirred for 24hours, filtered to remove pentafluorophenol byproduct, and the solventwas evaporated in vacuo. The residue was dissolved in methylenechloride, allowed to stand about 30 minutes, and filtered to removeadditional precipitated pentafluorophenol byproduct. Thepentafluorophenol byproduct was quantitatively recovered. The organicphase was then treated with saturated NaHCO₃ (200 mL), brine (200 mL),water (200 mL), dried over MgSO₄, and concentrated in vacuo. The crudeproduct was purified by column chromatography (silica, 1:1 ethylacetate/hexanes) to provide the desired product as an oil that slowlysolidified to a yellow solid. Yield: (90%). The ¹H NMR was consistentwith the desired product (FIG. 12). ¹H-NMR (400 MHz in CDCl₃): δ 9.25(s, 1H, ArH), 8.45 (d, 1H, ArH), 7.70 (d, 1H, ArH), 4.70 (d, J=10.8 Hz,2H, CH_(a)H_(b)), 4.55 (t, 2H, COOCH₂), 4.25 (d, J=10.8 Hz, 2H,CH_(a)H_(b)), 3.40 (t, 2H, SCH₂), 1.35 (s, 3H, CCH₃).

Example 13 Preparation of5-methyl-5-(N-isopropylamino)carboxyl-1,3-dioxane-2-one (MTC-NiP), (20)

MTC-PhF₅ (500 mg, 1.54 mmol) and CsF (117 mg, 0.77 mmol) were mixed inTHF (2 mL) and cooled by ice-salt bath. A solution of isopropylamine(200 microliters, 2.31 mmol) in THF (2 mL) was gently added to themixture and the reaction mixture was stirred for 30 minutes before thereaction mixture was allowed to warm to room temperature. After anadditional 16 hours stirring, the solvent was removed under vacuum,methylene chloride was added to the residue, and the insoluble materialwas filtered. The dried filtrate was concentrated under vacuum, and theresidue was recrystallized from a mixture of ethyl acetate and diethylether to provide the product MTC-NiP as a white solid (225 mg, 72%). ¹HNMR (400 MHz, CDCl₃): δ 5.74 (b, 1H, NH), 4.67 (d, 2H, CH₂O), 4.21 (d,2H, CH₂O), 4.15-4.05 (m, 1H, CH), 1.32 (s, 3H, CH₃), 1.17 (d, 6H,CHCH₃). ¹³C NMR (100 MHz, CDCl₃): δ 169.1, 147.8, 73.8, 42.1, 39.7,22.2, 17.6.

Example 14 Preparation of5-methyl-5-(N,N-dimethylamino)carboxyl-1,3-dioxane-2-one (MTC-NMe₂),(21)

The synthesis was conducted by the same procedure and the samestoichiometry used for MTC-NiP in Example 13, using 2.0 M THF solutionof dimethylamine as the amine in place of isopropylamine. The crudeproduct MTC-NMe₂ was also purified by recrystallization (EtOAc/Et₂O) toyield a white solid (177 mg, 61.3%). ¹H NMR (400 MHz, CDCl₃): δ 4.66 (d,2H, CH₂O), 4.33 (d, 2H, CH₂O), 3.03 (s, 6H, NCH₃), 1.50 (s, 3H, CH₃).¹³C NMR (100 MHz, CDCl₃): δ 169.7, 148.1, 73.6, 39.8, 37.5, 17.5.

Example 15 Synthesis of 5-methyl-5-trifluoroethoxylcarbonyl-1,3-dioxane-2-one (MTC-TFE), (22)

A THF solution (2 mL) of 2,2,2-trifluoroethanol (233 microliters, 3.20mmol) was slowly added to a mixture of MTC-PhF₅ (1.0 g, 3.1 mmol) andCsF (193 mg, 1.27 mmol) in THF (4 mL) at room temperature and thereaction mixture was kept stirring for 17 hours before the solvent wasdried under vacuum. The residue was then dissolved in methylenechloride, the insoluble material was filtered, the filtrate was driedand concentrated in vacuo to give the product MTC-TFE as a clear oil(616 mg, 81.7%). ¹H NMR (400 MHz, CDCl₃): δ 4.74 (d, 2H, CH₂O), 4.61 (q,2H, CH₂CF₃), 4.25 (d, 2H, CH₂O), 1.39 (s, 3H, CH₃). ¹³C NMR (100 MHz,CDCl₃): δ 169.8, 147.1, 122.4 (q), 72.5, 61.1(q), 40.4, 17.0.

Part II. Detailed Description

The following description includes additional embodiments relating tothe above-described Methods 2 (functionalization of the first cycliccarbonyl monomer bearing a pentafluorophenyl ester group) and Method 3(ring opening polymerization of the first and second cyclic carbonylmonomers) of the parent disclosure. Method 4 (functionalization of a ROPpolymer comprising a pentafluorophenyl ester group) is disclosed below.

The term “biodegradable” is defined by the American Society for Testingand Materials as a degradation caused by biological activity, especiallyby enzymatic action, leading to a significant change in the chemicalstructure of the material. For purposes herein, a material isbiodegradable if it undergoes 60% biodegradation within 180 days inaccordance with ASTM D6400.

Part II, Method 1. First Cyclic Monomers

The precursor compounds for the first cyclic carbonyl monomers can havethe general formula (23):

wherein

together the X groups are cyclic carbonyl forming nucleophilic groups,

each X independently represents a monovalent radical selected from thegroup consisting of —OH, —SH, —NH₂, and —NHR″, wherein each R″ groupindependently represents a monovalent radical selected from the groupconsisting of alkyl groups comprising 1 to 30 carbons, aryl groupscomprising 6 to 30 carbons, and the foregoing R″ groups substituted witha pentafluorophenyl ester forming carboxylic acid group,

n′ is 0 or an integer from 1 to 10, wherein when n′ is 0 carbons labeled1 and 3 attached to each X group are linked together by a single bond,

each R′ group independently represents a monovalent radical selectedfrom the group consisting of hydrogen, pentafluorophenyl ester formingcarboxylic acid groups, halides, alkyl groups comprising 1 to 30carbons, alkene groups comprising 1 to 30 carbons, alkyne groupscomprising 1 to 30 carbons, aryl groups comprising 6 to 30 carbons,ester groups comprising 1 to 30 carbons, amide groups comprising 1 to 30carbons, thioester groups comprising 1 to 30 carbons, urea groupscomprising 1 to 30 carbons, carbamate groups comprising 1 to 30 carbons,ether groups comprising 1 to 30 carbons, alkoxy groups comprising 1 to30 carbons, and the foregoing R′ groups substituted with apentafluorophenyl ester forming carboxylic acid group, and

at least one of the foregoing R′ and/or R″ groups comprises apentafluorophenyl ester forming carboxylic acid group.

The R′ and R″ groups can further independently comprise a cycloaliphaticring, an aromatic ring, and/or a heteroatom such as oxygen, sulfur ornitrogen. In an embodiment, the X groups of the precursor compound arehydroxy groups capable of forming a cyclic carbonate in a reaction withPFC.

Non-limiting examples of cyclic carbonyl forming moieties include1,2-ethanediol groups, 1,3-propanediol groups, 1,4-butanediol groups,1,2-ethanediamine groups, 1,3-propanediamine groups, 1,4-butanediaminegroups, 2-aminoethanol groups, 3-amino-1-propanol groups,4-amino-1-butanol groups, 2-mercaptoethanol groups,3-mercapto-1-propanol groups, 1-mercapto-2-propanol groups,4-mercapto-1-butanol groups, cysteamine groups, 1,2-ethanedithiolgroups, and 1,3-propanedithiol groups. Cyclic carbonyl groups formed bythe foregoing moieties in a reaction with PFC include cyclic carbonatesfrom any of the above diols, cyclic ureas from any of the abovediamines, cyclic carbamates from any of the above amino-alcohols, cyclicthiocarbonates from any of the above mercapto-alcohols, cyclicthiocarbamates from any of the above amino-thiols, and cyclicdithiocarbonates from any of the above dithiols. These functional groupsare listed in Table 1.

TABLE 1 Cyclic Carbonate

Cyclic Urea

Cyclic Carbamate

Cyclic Thiocarbamate

Cyclic Thiocarbonate

Cyclic Dithiocarbonate

The first cyclic carbonyl compound comprises a cyclic carbonyl moietyselected from the group consisting of cyclic carbonates, cycliccarbamates, cyclic ureas, cyclic thiocarbonates, cyclic thiocarbamates,cyclic dithiocarbonates, and combinations thereof, formed by reaction ofthe two X groups with PFC. The first cyclic carbonyl compound furthercomprises a pendant pentafluorophenyl ester group (i.e., the moiety—CO₂C₆F₅) derived from a pentafluorophenyl ester forming carboxylic acidgroup of an R′ and/or R″ group.

The first cyclic carbonyl compounds can be represented by the generalformula (24):

wherein

each Y is a divalent radical independently selected from the groupconsisting of —O—, —S—, —N(H)—, or —N(Q″)-, wherein each Q″ group is amonovalent radical independently selected from the group consisting ofalkyl groups comprising 1 to 30 carbons, aryl groups comprising 6 to 30carbons, and the foregoing Q″ groups substituted with apentafluorophenyl ester group (i.e., —CO₂C₆F₅),

n′ is 0 or an integer from 1 to 10, wherein when n′ is 0, carbonslabeled 4 and 6 are linked together by a single bond,

each Q′ group is a monovalent radical independently selected from thegroup consisting of hydrogen, halides, pentafluorophenyl ester group,alkyl groups comprising 1 to 30 carbons, alkene groups comprising 1 to30 carbons, alkyne groups comprising 1 to 30 carbons, aryl groupscomprising 6 to 30 carbons, ester groups comprising 1 to 30 carbons,amide groups comprising 1 to 30 carbons, thioester groups comprising 1to 30 carbons, urea groups comprising 1 to 30 carbons, carbamate groupscomprising 1 to 30 carbons, ether groups comprising 1 to 30 carbons,alkoxy groups comprising 1 to 30 carbons, and the foregoing Q′ groupssubstituted with a pentafluorophenyl ester group, and wherein

one or more of the Q′ and/or Q″ groups comprises a pentafluorophenylester group.

The Y groups in formula (24) are derived from the X groups of formula(1). In an embodiment, each Y in formula (24) is —O— and the firstcyclic carbonyl compound comprises a cyclic carbonate group. In anotherembodiment, the first cyclic carbonyl compound comprises a singlependant pentafluorophenyl ester group.

The cyclic carbonyl group and the pendant pentafluorophenyl ester moietyare formed in one step from the precursor compound using PFC and asuitable catalyst. PFC is less toxic than other reagents (e.g.,phosgene) in preparing cyclic carbonate compounds. PFC is a crystallinesolid at room temperature that, being less sensitive to water thanphosgene, can be easily stored, shipped, and handled. PFC does notrequire elaborate reaction and workup conditions. Moreover, thepentafluorophenol byproduct of the cyclization reaction is lessvolatile, less acidic, and less corrosive than hydrochloric acid. Theseadvantages reduce the cost and complexity of the reactions, andpotentially widen the scope of the starting materials to includecompounds containing acid-sensitive groups. In addition, thepentafluorophenol byproduct of the cyclization reaction can be readilyrecycled back into PFC.

Isomerically pure precursor compounds having a hydrogen attached to anasymmetric carbon can be converted to a cyclic carbonyl compoundcomprising a pentafluorophenyl ester group without undergoingsignificant racemization. The esterification conditions are effective inachieving an enantiomeric excess of 80% or more, more specifically of90% or more. In an embodiment, the cyclic carbonyl compound comprises anasymmetric carbon as an (R) isomer, in an enantiomeric excess of greaterthan 80%, more specifically greater than 90%. In another embodiment, thecyclic carbonyl compound comprises an asymmetric carbon as an (S)isomer, in an enantiomeric excess greater than 80%, more specificallygreater than 90%.

Other precursor compounds are represented by the general formula (25):

wherein

the X′ groups together are cyclic carbonyl forming nucleophilic groups,

m and n are each independently 0 or an integer from 1 to 11, wherein mand n cannot together be 0, and m+n is an integer less than or equal to11,

each X′ is a monovalent radical independently selected from the groupconsisting of —OH, —SH, —NH₂, and —NHT″, wherein each T″ is a monovalentradical independently selected from the group consisting of alkyl groupscomprising 1 to 30 carbons, aryl groups comprising 6 to 30 carbons, andthe foregoing T″ groups substituted with a pentafluorophenyl esterforming carboxylic acid group, and each T′ is a monovalent radicalindependently selected from the group consisting of hydrogen, halides,pentafluorophenyl ester forming carboxylic acid groups, alkyl groupscomprising 1 to 30 carbons, alkene groups comprising 1 to 30 carbons,alkyne groups comprising 1 to 30 carbons, aryl groups comprising 6 to 30carbons, ester groups comprising 1 to 30 carbons, amide groupscomprising 1 to 30 carbons, thioester groups comprising 1 to 30 carbons,urea groups comprising 1 to 30 carbons, carbamate groups comprising 1 to30 carbons, ether groups comprising 1 to 30 carbons, alkoxy groupscomprising 1 to 30 carbons, and the foregoing T′ groups substituted witha pentafluorophenyl ester forming carboxylic acid group, and

L′ is a single bond or a divalent linking group selected from the groupconsisting of alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, thioester groupscomprising 1 to 30 carbons, urea groups comprising 1 to 30 carbons,carbamate groups comprising 1 to 30 carbons, and ether groups comprising1 to 30 carbons.

The T′ and T″ groups can further independently comprise a cycloaliphaticring, an aromatic ring, and/or a heteroatom such as oxygen, sulfur ornitrogen. In an embodiment, none of the T′ or T″ groups comprises apentafluorophenyl ester forming carboxylic acid group, and L′ is asingle bond joining carbon labeled 2 of formula (25) with the carboxylicacid group. In another embodiment, the T′ group attached to carbonlabeled 2 in formula (25) is ethyl or methyl, and all other T′ groupsare hydrogen. In another embodiment, the T′ group attached to carbonlabeled 2 in formula (25) is ethyl or methyl, carbon labeled 2 informula (25) is an asymmetric center, and the precursor compoundcomprises the (R) or (S) isomer in greater than 80% enantiomeric excess.

The corresponding first cyclic carbonyl compounds formed by theprecursor compounds of formula (25) have the general formula (26):

wherein

m and n are each independently 0 or an integer from 1 to 11, wherein mand n cannot together be 0, and m+n is an integer less than or equal to11,

each Y′ is a divalent radical independently selected from the groupconsisting of —O—, —S—, —N(H)— and —N(V″)—, wherein each V″ group is amonovalent radical independently selected from the group consisting ofalkyl groups comprising 1 to 30 carbons, aryl groups comprising 1 to 30carbons, and the foregoing V″ groups substituted with apentafluorophenyl ester group (—CO₂C₆F₅),

each V′ group is a monovalent radical independently selected from thegroup consisting of hydrogen, halides, pentafluorophenyl ester group,alkyl groups comprising 1 to 30 carbons, alkene groups comprising 1 to30 carbons, alkyne groups comprising 1 to 30 carbons, aryl groupscomprising 6 to 30 carbons, ester groups comprising 1 to 30 carbons,amide groups comprising 1 to 30 carbons, thioester groups comprising 1to 30 carbons, urea groups comprising 1 to 30 carbons, carbamate groupscomprising 1 to 30 carbons, ether groups comprising 1 to 30 carbons,alkoxy groups comprising 1 to 30 carbons, and the foregoing V′ groupssubstituted with a pentafluorophenyl ester group, and

L′ is a single bond or a divalent linking group selected from the groupconsisting of alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, thioester groupscomprising 1 to 30 carbons, urea groups comprising 1 to 30 carbons,carbamate groups comprising 1 to 30 carbons, and ether groups comprising1 to 30 carbons.

In an embodiment, no V′ group and no V″ group comprises apentafluorophenyl ester group, and L′ is a single bond joining carbonlabeled 5 of formula (26) to the pentafluorophenyl ester group. Inanother embodiment, the V′ group attached to the carbon labeled 5 informula (26) is ethyl or methyl, and all other V′ groups are hydrogen.In an embodiment, the V′ group attached to carbon labeled 5 in formula(26) is ethyl or methyl, carbon labeled 5 in formula (26) is anasymmetric center, and the cyclic carbonyl compound comprises the (R) or(S) isomer in greater than 80% enantiomeric excess. In anotherembodiment, each Y′ is —O—, and V′ at position labeled 5 in formula (26)is a monovalent radical selected from the group consisting of hydrogen,halides, and alkyl groups comprising 1 to 30 carbons.

Even more specific first cyclic carbonyl compounds are cyclic carbonateshaving the general formula (27):

wherein

m and n are each independently 0 or an integer from 1 to 11, wherein mand n cannot together be 0, and m+n is less than or equal to 11,

R¹ is a monovalent radical selected from the group consisting ofhydrogen, halides, and alkyl groups comprising 1 to 30 carbons,

each V′ group is monovalent radical independently selected from thegroup consisting of hydrogen, halides, pentafluorophenyl ester group(—CO₂C₆F₅), alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, thioester groupscomprising 1 to 30 carbons, urea groups comprising 1 to 30 carbons,carbamate groups comprising 1 to 30 carbons, ether groups comprising 1to 30 carbons, alkoxy groups comprising 1 to 30 carbons, and theforegoing V′ groups substituted with a pentafluorophenyl ester group,and

L′ is a single bond or a divalent linking group selected from the groupconsisting of alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, thioester groupscomprising 1 to 30 carbons, urea groups comprising 1 to 30 carbons,carbamate groups comprising 1 to 30 carbons, and ether groups comprising1 to 30 carbons.

R¹ and L′ can together form a first ring comprising 3 to 10 carbons.Each V′ can independently form a second ring with a different V′ group,with R¹, with L′, or combinations thereof, wherein the second ringcomprises 3 to 10 carbons.

In an embodiment, the cyclic carbonate compound of formula (27)comprises a single pentafluorophenyl ester group, and L′ is a singlebond joining carbon labeled 5 of formula (27) to the pentafluorophenylester group. In another embodiment,

each V′ is hydrogen. In another embodiment, m and n are equal to 1, andR¹ is a monovalent hydrocarbon group comprising 1 to 10 carbons. Inanother embodiment, R¹ is selected from the group consisting of methyl,ethyl, propyl, 2-propyl, n-butyl, 2-butyl, sec-butyl (2-methylpropyl),t-butyl (1,1-dimethylethyl), n-pentyl, 2-pentyl, 3-pentyl, iso-pentyl,and neo-pentyl.

Even more specific first cyclic carbonate monomers are represented bythe general formula (28):

wherein

m and n are each independently 0 or an integer from 1 to 11, wherein mand n cannot together be 0, and m+n is less than or equal to 11,

R¹ is a monovalent radical selected from the group consisting ofhydrogen, halides, and alkyl groups comprising 1 to 30 carbons, and

L′ is a single bond or a divalent linking group selected from the groupconsisting of alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, thioester groupscomprising 1 to 30 carbons, urea groups comprising 1 to 30 carbons,carbamate groups comprising 1 to 30 carbons, and ether groups comprising1 to 30 carbons.

R¹ and L′ can together form a first ring comprising 3 to 10 carbons.Each V′ can independently form a second ring with a different V′ group,with R¹, with L′, or combinations thereof, wherein the second ringcomprises 3 to 10 carbons.

In an embodiment, m and n are each independently 0 or an integer from 1to 3, wherein m and n together cannot be 0, and L′ is a single bondjoining carbon labeled 5 of formula (28) to the pentafluorophenyl estergroup. In another embodiment, m and n are each equal to 1, and R¹ is amonovalent hydrocarbon group comprising 1 to 10 carbons. Exemplary R¹groups include, for example, methyl, ethyl, propyl, 2-propyl, n-butyl,2-butyl, sec-butyl (2-methylpropyl), t-butyl (1,1-dimethylethyl),n-pentyl, 2-pentyl, 3-pentyl, iso-pentyl, and neo-pentyl.

Exemplary precursor compounds for preparing cyclic carbonate compoundsbearing a pendant pentafluorophenyl ester group include but are notlimited to bis(hydroxy) alkanoic acids, including bis(hydroxymethyl)alkanoic acids, such as 2,2-bis(hydroxymethyl)propionic acid,2,2-bis(hydroxymethyl)butanoic acid, 2,2-bis(hydroxymethyl)pentanoicacid, 2,2-bis(hydroxymethyl)hexanoic acid, and4,4-bis(hydroxymethyl)pentanoic acid. Other exemplary precursorcompounds include 2,2,5,5-tetrakis(hydroxymethyl)adipic acid, and2-[2,2-bis(hydroxymethyl)butoxycarbonyl]cyclopropane-1-carboxylic acid.

In an embodiment, the first cyclic carbonate compound is selected fromthe group consisting of

Method 1. Preparation of the First Cyclic Carbonyl Compound

A method (Method 1) of preparing a first cyclic carbonyl compoundbearing a pendant pentafluorophenyl ester group comprises forming afirst mixture comprising bis(pentafluorophenyl) carbonate, a catalyst,an optional solvent, and a precursor compound, the precursor compoundcomprising i) three or more carbons, ii) a carboxylic acid group capableof forming a pentafluorophenyl ester group in a reaction withbis(pentafluorophenyl) carbonate, and iii) at least two nucleophilicgroups (e.g., the X groups in formula (23)) independently selected fromthe group consisting of hydroxy group, primary amines, secondary amines,and thiol group, the two nucleophilic groups capable of forming a cycliccarbonyl group in a reaction with bis(pentafluorophenyl) carbonate. Thefirst mixture is agitated at a temperature effective in forming a firstcyclic carbonyl compound. The first cyclic carbonyl compound comprisesi) a pendant pentafluorophenyl ester group and ii) a cyclic carbonylmoiety selected from the group consisting of cyclic carbonates, cyclicureas, cyclic carbamates, cyclic thiocarbamates, cyclic thiocarbonates,and cyclic dithiocarbonates.

The formation of the cyclic carbonyl moiety and the pendantpentafluorophenyl ester group can occur in a single process step undermild conditions.

The precursor compound can comprise more than one pentafluorophenylester forming carboxylic acid group and more than two nucleophilicgroups capable of forming a cyclic carbonyl group in a reaction withbis(pentafluorophenyl) carbonate. Consequently, the first cycliccarbonyl monomer can comprise more than one cyclic carbonyl moiety andmore than one pendant pentafluorophenyl ester group. In an embodiment,the first cyclic carbonyl compound comprises one pentafluorophenyl estergroup. In another embodiment, the first cyclic carbonyl compoundcomprises one cyclic carbonyl moiety.

A method of preparing a first cyclic carbonyl monomer comprises forminga first mixture comprising i) a precursor compound, ii)bis(pentafluorophenyl) carbonate, iii) a catalyst, and iv) an optionalsolvent, wherein the precursor compound comprises a) three or morecarbons, b) two nucleophilic groups capable together of forming a cycliccarbonate group, the nucleophilic groups independently selected from thegroup consisting of hydroxy group, primary amines, secondary amines, andthiol group, and c) a carboxylic acid group; and agitating the firstmixture, thereby forming a first cyclic carbonyl compound comprising apendant pentafluorophenyl ester group, the cyclic carbonyl compoundcomprising a cyclic carbonyl moiety selected from the group consistingof cyclic carbonates, cyclic ureas, cyclic carbamates, cyclicthiocarbamates, cyclic thiocarbonates, and cyclic dithiocarbonates.

A specific method of preparing a first cyclic carbonate compoundcomprises forming a first mixture comprising i) a precursor compound,ii) bis(pentafluorophenyl) carbonate, and iii) a catalyst, wherein theprecursor compound comprises a) three or more carbons, b) two hydroxygroups capable together of forming a cyclic carbonate group, and c) acarboxylic acid group; and agitating the first mixture, thereby forminga first cyclic carbonate compound comprising a pendant pentafluorophenylester group.

An even more specific method of forming a first cyclic carbonyl monomercomprises agitating a first mixture comprising i) a precursor compoundcomprising two or more carbons, two or more hydroxy groups, and one ormore carboxy groups, ii) bis(pentafluorophenyl) carbonate, and iii) acatalyst, thereby forming a first cyclic carbonate compound comprising apendant pentafluorophenyl ester group.

Part II, Method 2. Functionalization of the First Cyclic Monomer

Also disclosed is a mild method (Method 2) of preparing a second cycliccarbonyl compound from the first cyclic carbonyl compound by selectivelyreacting the first cyclic carbonyl compound with a nucleophile such asan alcohol, amine, or thiol, without altering the cyclic carbonyl moietyof the first cyclic carbonyl compound, thereby forming a second cycliccarbonyl compound and pentafluorophenol byproduct. In this reaction, thependant pentafluorophenyl ester group is converted to a secondfunctional group selected from the group consisting of alcohol basedesters other than pentafluorophenyl ester, carbamates, andthiocarbonates. The second functional group can comprise from 1 to 10000carbons. An optional catalyst can be used with weaker nucleophiles suchas alcohols when forming the second cyclic carbonyl compound. Generally,a catalyst is not required for the reaction of a pendantpentafluorophenyl ester group with stronger nucleophiles (e.g., primaryamines). In an embodiment, the second cyclic carbonyl compound comprisesno pentafluorophenyl ester groups.

The second cyclic carbonyl compounds can have the general formula (29):

wherein

n′ is 0 or an integer from 1 to 10, wherein when n′ is 0 carbons labeled4 and 6 are linked together by a single bond,

each W′ is a divalent radical independently selected from the groupconsisting of —O—, —S—, —N(H)— or —N(W″)′, wherein each W″ groupindependently represents a monovalent radical selected from the groupconsisting of alkyl groups comprising 1 to 30 carbons, aryl groupscomprising 1 to 30 carbons, and the foregoing W″ groups substituted witha second functional group selected from the group consisting of alcoholbased esters other than pentafluorophenyl ester, amides, and thioesters,

each Z′ group independently represents a monovalent radical selectedfrom the group consisting of hydrogen, the second functional group,halides, alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, aryl groups comprising6 to 30 carbons, thioester groups comprising 1 to 30 carbons, ureagroups comprising 1 to 30 carbons, carbamate groups comprising 1 to 30carbons, ether groups comprising 1 to 30 carbons, alkoxy groupscomprising 1 to 30 carbons, and the foregoing Z′ groups substituted witha second functional group selected from the group consisting of alcoholbased esters other than pentafluorophenyl ester, amides, and thioesters,and

the second cyclic carbonyl compound comprises no pentafluorophenyl estergroup (—CO₂ PFP) and no pentafluorophenyl carbonate group (—OCO₂ PFP).

A more specific second cyclic carbonyl compound has the general formula(30):

wherein

m and n are each independently 0 or an integer from 1 to 11, wherein mand n cannot together be 0, and m+n equals an integer from 1 to 11,

each W′ independently represents divalent radical selected from thegroup consisting of O, S, NH or NW″, wherein each W″ group independentlyrepresents a monovalent radical selected from the group consisting ofalkyl groups comprising 1 to 30 carbons, and aryl groups comprising 1 to30 carbons, and the foregoing W″ groups substituted with a secondfunctional group selected from the group consisting of alcohol basedesters other than pentafluorophenyl ester, amides, and thioesters,

L′ represents a single bond or a divalent linking group selected fromthe group consisting of alkyl groups comprising 1 to 30 carbons, alkenegroups comprising 1 to 30 carbons, alkyne groups comprising 1 to 30carbons, aryl groups comprising 6 to 30 carbons, ester groups comprising1 to 30 carbons, amide groups comprising 1 to 30 carbons, thioestergroups comprising 1 to 30 carbons, urea groups comprising 1 to 30carbons, carbamate groups comprising 1 to 30 carbons, and ether groupscomprising 1 to 30 carbons,

each Q′ group independently represents a monovalent radical selectedfrom the group consisting of hydrogen, the second functional group,halides, alkyl groups comprising 1 to 30 carbons, alkene groupscomprising 1 to 30 carbons, alkyne groups comprising 1 to 30 carbons,aryl groups comprising 6 to 30 carbons, ester groups comprising 1 to 30carbons, amide groups comprising 1 to 30 carbons, thioester groupscomprising 1 to 30 carbons, urea groups comprising 1 to 30 carbons,carbamate groups comprising 1 to 30 carbons, ether groups comprising 1to 30 carbons, and alkoxy groups comprising 1 to 30 carbons, and any ofthe foregoing Q′ groups substituted with a second functional groupselected from the group consisting of alcohol based esters other thanpentafluorophenyl ester, amides, and thioesters,

each X″ is a divalent radical independently selected from the groupconsisting of —O—, —S—, —N(H)—, and —N(R³)—,

each R² and R³ is independently a monovalent radical comprising 1 to10,000 carbons, and

the second cyclic carbonyl compound contains no pentafluorophenyl estergroup and no pentafluorophenyl carbonate group.

In an embodiment, each W′ is —O— (i.e., the second cyclic carbonylcompound is a cyclic carbonate). In another embodiment, the Q′ groupattached to the carbon 5 in formula (30) is ethyl or methyl, and allother Q′ groups are hydrogen. In another embodiment, carbon 5 in formula(30) is an asymmetric center, and the cyclic carbonyl compound comprisesthe (R) or (S) isomer in greater than 80% enantiomeric excess.

Even more specific second cyclic carbonyl compounds derived from thefirst cyclic carbonyl monomer are cyclic carbonates of the generalformula (31):

wherein

m and n are each independently 0 or an integer from 1 to 11, wherein mand n cannot together be 0; and m+n equals an integer from 1 to 11,

L′ represents a single bond or a divalent linking group selected fromthe group consisting of alkyl groups comprising 1 to 30 carbons, alkenegroups comprising 1 to 30 carbons, alkyne groups comprising 1 to 30carbons, aryl groups comprising 6 to 30 carbons, ester groups comprising1 to 30 carbons, amide groups comprising 1 to 30 carbons, thioestergroups comprising 1 to 30 carbons, urea groups comprising 1 to 30carbons, carbamate groups comprising 1 to 30 carbons, and ether groupscomprising 1 to 30 carbons;

R¹ is a monovalent radical selected from the group consisting ofhydrogen, halides, and alkyl groups comprising 1 to 30 carbons;

each X″ is a divalent radical independently selected from the groupconsisting of —O—, —S—, —N(H)—, and —N(R³)—; and

each R² and R³ is independently a monovalent radical comprising 1 to10,000 carbons; and

the second cyclic carbonyl compound contains no pentafluorophenyl estergroup and no pentafluorophenyl carbonate group.

The reaction to form the second functional group occurs withoutdisrupting the cyclic carbonyl moiety, in particular the cycliccarbonate moiety, of the first cyclic carbonyl compound. The byproductof the displacement reaction, pentafluorophenol, can be recovered andrecycled, typically in high yield. The second cyclic carbonate compoundsare potentially capable of forming ROP polycarbonates and other polymersby ROP methods. The ROP polymers can have unique pendant functionalitiesand properties due to the wide variety of available materials for thependant —X″—R² group in formula (29), formula (30), and formula (31).

The method (Method 2) of preparing a second cyclic carbonyl compoundcomprises agitating a mixture comprising the first cyclic carbonylcompound comprising a pentafluorophenyl ester group; an optionalsolvent; an optional catalyst; and a nucleophile selected from the groupconsisting of alcohols, amines, and thiols, thereby forming a secondcyclic carbonyl monomer and pentafluorophenol byproduct, wherein thesecond cyclic carbonyl monomer comprises a second functional groupselected from the group consisting of alcohol based esters other thanpentafluorophenyl ester, amides, and thioesters formed by a reaction ofthe pentafluorophenyl ester group with the nucleophile.

Additional alcohols to those listed in Part I that are capable oftransesterifying a pentafluorophenyl ester of the first cyclic carbonylmonomer without altering the cyclic carbonyl group include:

Additional non-limiting examples of amines capable of reacting with thepentafluorophenyl ester group to form a pendant amide, without alteringthe cyclic carbonate group, include:

Non-limiting examples of thiols capable of reacting with the pendant PFPester to form a pendant thioester without altering the cyclic carbonylgroup include: methane thiol, ethane thiol, phenylthiol, benzyl thiol,and the like.

In general, the efficacy of the substitution reactions proceed inaccordance with the nucleophilicity of the nucleophiles. For example,stronger nucleophiles such as primary amines are more effective thanweaker nucleophiles such as primary alcohols. In another example,primary and secondary alcohols can be more effective nucleophiles thansterically hindered alcohols such as tert-butanol in a reaction with thependant pentafluorophenyl ester group.

The nucleophile in Method 2 can be a polymeric alcohol. The polymericalcohol can comprise from 4 to 10000 carbons. In one example, thenucleophile is a polyether alcohol, and the pentafluorophenyl estergroup of the first cyclic carbonyl compound reacts with the polyetheralcohol to form a second cyclic carbonyl containing material comprisinga pendant hydrophilic polyether ester group, exemplified by monomerMTCOMPEG (Table 3 further below).

Non-limiting examples of polymeric alcohols include polyether alcohols,such as polyethylene glycol (PEG), and mono end capped polyethyleneglycol, such as monomethyl endcapped polyethylene glycol (MPEG):

Other polymeric alcohols include polypropylene glycol (PPG) and monoendcapped derivatives thereof, such as monomethyl end cappedpolypropylene glycol (MPPG):

Still other polymeric alcohols include poly(alkylene glycols) offormulas (32), (33), and (34) described further below.

Generally, the first mixture (Method 2) is agitated at a temperature of−78° C. to 100° C., more specifically 20° C. to 50° C., and even morespecifically 10° C. to 30° C. to form the second cyclic carbonylcompound. In an embodiment, agitation to convert the pentafluorophenylester to a different alcohol based ester, amide, or thioester isconducted at ambient temperature (herein, 17° C. to 30° C.). The firstmixture is agitated for a period of about 1 hour to about 48 hours, moreparticularly about 20 to 30 hours at the reaction temperature. In anembodiment, the first cyclic carbonyl compound and the second cycliccarbonyl compound are each a cyclic carbonate.

Generally, 1.2 to 1.5 equivalents of the nucleophile with respect to thepentafluorophenyl ester are used in the substitution reaction. When alarge excess nucleophile is used (e.g., more than 4 equivalents),ring-opening of the cyclic carbonate can occur as a side reaction.

Typically, a solvent is used in Method 2, though a solvent is notrequired. Depending on the solvent, the pentafluorophenol byproduct canin some instances precipitate directly from the reaction mixture as itis formed. The second cyclic carbonyl compound can be isolated using anyknown method of purification, including distillation, chromatography,extraction, precipitation, and recrystallization. Generally, however,the second mixture is concentrated under vacuum and the resultingresidue is then treated with a second solvent in which thepentafluorophenol byproduct is not soluble, such as methylene chloride.The pentafluorophenol byproduct can then be filtered and recovered forrecycling back to PFC. In an embodiment, 90% to 100% of the theoreticalpentafluorophenol byproduct is recovered for recycling back to PFC. Inone variation, the derived second cyclic carbonate compound can beisolated by washing the organic filtrate with a base such as sodiumbicarbonate solution, drying the filtrate with a drying agent such asmagnesium sulfate or sodium sulfate, and evaporating the second solventunder vacuum. In a another variation, the second cyclic carbonylcompound is further purified by column chromatography orrecrystallization. In this manner the second cyclic carbonyl compoundcan be obtained in a yield of about 50% to about 100%, more particularlyabout 70% to 100%, even more particularly about 80% to 100%.

The optional catalyst of Method 2 can be selected from typical catalystsfor transesterifications, conversions of esters to amides, or conversionof esters to thioesters. These include organic catalysts and inorganiccatalysts, in particular the above described catalysts, and mostspecifically cesium fluoride. When used in Method 2, the catalyst can bepresent in an amount of 0.02 to 1.00 moles per mole of the first cycliccarbonyl compound, more particularly 0.05 to 0.50 moles per mole of thefirst cyclic carbonyl compound, and even more particularly 0.15 to 0.25moles per mole of the first cyclic carbonyl compound.

In an additional embodiment, Method 1 and Method 2 are performedstep-wise in a single reaction vessel, without an intermediate step toisolate the first cyclic carbonyl compound.

The above-described methods provide a controlled process for introducinga wide range of functionality and connectivity into cyclic carbonylcompounds for ring-opening polymerizations. As stated above, the cycliccarbonyl compounds (first and/or second cyclic carbonyl compounds) canbe formed in isomerically pure form, or as racemic mixtures.

Part II, Method 3. Ring Opening Polymerization of the First CyclicMonomer

As described in Part I, ROP polymers can be obtained by nucleophilicring opening polymerization of the above described first and secondcyclic carbonyl compounds. The ROP polymer comprises a chain fragmentderived from the nucleophilic initiator for the ROP polymerization, anda first polymer chain linked to the chain fragment. The chain fragmentis also referred to herein as the initiator fragment. The initiatorfragment comprises at least one oxygen, nitrogen, and/or sulfur backboneheteroatom, which is a residue of a respective alcohol, amine, or thiolnucleophilic initiator group of the ROP initiator. The backboneheteroatom is linked to the first end unit of the first polymer chaingrown therefrom. A second end unit of the first polymer chain can be aliving end unit capable of initiating additional ring openingpolymerization, if desired. A living second end unit comprises anucleophilic group selected from the group consisting of hydroxy group,primary amines, secondary amines, and thiol group. Alternatively, thesecond end unit can be endcapped to impart stability to the ROP polymer,as described further below.

It is understood that the initiator fragment has a different structurethan the first end unit of each ROP polymer chain connected thereto.

The ROP initiator can comprise one or more independently chosen alcohol,amine, or thiol nucleophilic initiator groups. Each nucleophilicinitiator group can potentially initiate a ring opening polymerization.Likewise, the initiator fragment comprises at least one backboneheteroatom derived from a nucleophilic initiator group. Each one of thebackbone heteroatoms that is derived from a nucleophilic initiator groupis linked to a ROP polymer chain grown therefrom. Thus, an initiatorcomprising n nucleophilic initiator groups can potentially initiateformation of n independent ROP polymer chains, where n is an integerequal to or greater than 1. As a non-limiting example, a dinucleophilicinitiator comprising two hydroxy groups can initiate a ring openingpolymerization at each hydroxy group. The product ROP polymer comprisesan initiator fragment linked to two ROP polymer chains through the twobackbone oxygens derived from the hydroxy initiator groups.

The ROP polymer comprises a first polymer chain. The first polymer chaincan comprise a homopolymer, random copolymer, block copolymer, orcombinations of the foregoing polymer types. The first polymer chaincomprises a first repeat unit comprising a backbone functional groupselected from the group consisting of carbonate, ureas, carbamates,thiocarbamates, thiocarbonate, and dithiocarbonate. The first repeatunit further comprises a tetrahedral backbone carbon. In an embodiment,the tetrahedral backbone carbon is linked to a first side chaincomprising a pendant pentafluorophenyl ester group. In anotherembodiment, the tetrahedral backbone carbon is linked to a first sidechain comprising a pendant pentafluorophenyl ester group, and to asecond side chain selected from the group consisting of hydrogen,halides, and alkyl groups comprising 1 to 30 carbons (e.g., the R¹ groupas described in formulas (27) and (28)).

In the following non-limiting examples, R′—XH is an mono-nucleophilicinitiator for ring opening polymerization. R′—XH comprises a monovalentinitiator group —XH, wherein X is a divalent group selected from thegroup consisting of —O—, —NH—, —N(R″)—, and —S—. No restriction isplaced on the structure of R′ or R″ with the proviso that the ringopening polymerization produces a useful ROP polymer.

As one example, the nucleophilic ring opening polymerization of a firstcyclic carbonyl monomer of formula (24) initiated by R′—XH produces aROP polymer of formula (24A), which comprises a first polymer chainlinked to initiator fragment R′—X—.

Initiator fragment R′—X— is linked to the carbonyl of the first end unitof the ROP polymer chain by the oxygen, nitrogen or sulfur heteroatom ofthe X group. A second end unit of the ROP polymer chain remains a livingend unit (i.e., the —Y—H group in formula (24A)), wherein —Y—H is anucleophilic hydroxy group, primary amine group, secondary amine group,or thiol group. Y, Q′, and n′ are defined as above under formula (24);therefore, at least one of the Q′ groups and/or Q″ groups (of the Ygroups) comprises a pendant pentafluorophenyl ester group (—CO₂C₆F₅).The subscript d′ is an integer from 1 to 10000. The repeat unit

comprises a backbone functional group selected from the group consistingof carbonate, ureas, carbamates, thiocarbamates, thiocarbonate, anddithiocarbonate, determined by the independent selection of each Ygroup. The first repeat unit further comprises tetrahedral backbonecarbons labeled 4, 5 and 6. Each of these backbone carbons can be linkedto a first side chain Q′ which can comprise a pentafluorophenyl estergroup. Further, each of these tetrahedral backbone carbons can be linkedto an optional second side chain Q′ group, defined above under formula(24).

In another example, the nucleophilic ring opening polymerization of afirst cyclic carbonyl monomer of formula (26), initiated by R′—XH,produces a ROP polymer of formula (26A), which comprises a first polymerchain linked to initiator fragment R′—X—:

The initiator fragment R′—X— is linked to the carbonyl of the first endunit of the ROP polymer chain by the oxygen, nitrogen or sulfurheteroatom of the X group. Y′, L′,V′, n and m are defined as above underformula (26). The subscript d′ is an integer from 1 to 10000. The repeatunit

comprises a backbone functional group selected from the group consistingof carbonate, ureas, carbamates, thiocarbamates, thiocarbonate, anddithiocarbonate, determined by the independent selection of each Y′group. Tetrahedral backbone carbon 5 is linked to a first side chaincomprising a pentafluorophenyl ester group. Tetrahedral backbone carbon5 can optionally be linked to a second side chain V′ group, as definedabove under formula (26).

In another example, the nucleophilic ring opening polymerization of afirst cyclic carbonyl monomer of formula (27), initiated by R′—XH,produces a ROP polymer of formula (27A), which comprises a first polymerchain linked to initiator fragment R′—X—:

As above, the initiator fragment R′—X— is linked to the carbonyl of thefirst end unit of the ROP polymer chain by the oxygen, nitrogen orsulfur heteroatom of the X group. Y′, L, V′, n and m are defined asabove under formula (27). The subscript d′ is an integer from 1 to10000. The repeat unit

comprises a backbone functional group selected from the group consistingof carbonate, ureas, carbamates, thiocarbamates, thiocarbonate, anddithiocarbonate, determined by the independent selection of each Y′group. Tetrahedral backbone carbon labeled 5 is linked to a first sidechain comprising a pentafluorophenyl ester group, and to a second sidechain R′ defined above under formula (27). Tetrahedral backbone carbonslabeled 4 and 6 can independently be linked to independent first andsecond side chain V′ groups, as described above under formula (27).

In another example, the nucleophilic ring opening polymerization of afirst cyclic carbonyl monomer of formula (28), initiated by R′—XH,produces a polycarbonate of formula (28A), which comprises a firstpolycarbonate chain linked to initiator fragment R′—X—:

Initiator fragment R′—X— is linked by the oxygen, nitrogen or sulfurheteroatom of the X group to the carbonyl of the first end unit of theROP polycarbonate chain. R¹, L′, V′, m and n are defined as above underformula (28). The subscript d′ is an integer from 1 to 10000. The repeatunit

comprises a backbone carbonate group. Tetrahedral backbone carbonlabeled 5 is linked to a first side chain comprising a pentafluorophenylester group, and to a second side chain R¹ group defined above underformula (28).The ROP polymer can comprise two or more polymer chains. Additionally,each polymer chain can be a homopolymer of a respective first repeatunit, or a copolymer comprising a second repeat unit, the second repeatunit comprising a second backbone functional group selected from thegroup consisting of esters, carbonates, ureas, carbamates,thiocarbamates, thiocarbonates and dithiocarbonates, which is derivedfrom a cyclic carbonyl comonomer. The first polymer chain can be arandom copolymer or a block copolymer comprising the first and secondrepeat units.

Similar considerations apply to ROP polymers prepared from a secondcyclic carbonyl compound, except that the ROP polymer chain does notcomprise a pentafluorophenyl ester side chain group or apentafluorophenyl carbonate group. Instead, the ROP polymer comprises arepeat unit comprising a side chain comprising a different alcohol basedester group, amide group, or thioester group derived from the pendantpentafluorophenyl ester group of the first cyclic carbonyl monomer.

The first and/or second cyclic carbonyl compounds can undergoring-opening polymerization (ROP) to form biodegradable polymers havingdifferent tacticities. Atactic, syndiotactic and isotactic forms of thepolymers can be produced that depend on the cyclic carbonyl monomer(s),its isomeric purity, and the polymerization conditions.

The ring opening polymerization (ROP) of the first cyclic carbonylcompound can occur with substantial retention of the pentafluorophenylester group in the product ROP polymer, which is also referred to as thefirst ROP polymer. The first ROP polymer comprises at least one repeatunit comprising a side chain comprising a pendant pentafluorophenylester group. The first ROP polymer further comprises a backbone segmentderived from the ring opening of the first cyclic carbonyl compound, thebackbone segment selected from the group consisting of polycarbonates,polyureas polycarbamates, polythiocarbamates, polythiocarbonates, andpolydithiocarbonates. The first ROP polymer can further comprise apolyester backbone segment when a cyclic ester (lactone) comonomer isused in the ring opening polymerization. Each of these repeat structuresis shown in Table 2. The R group in Table 2 is a backbone fragmentformed by the carbons of the ring containing the cyclic carbonyl group.

TABLE 2 Polyester

Polycarbonate

Polyurea

Polycarbamate

Polythiocarbamate

Polythiocarbonate

Polydithiocarbonate

The method (Method 3) comprises forming a first mixture comprising afirst cyclic carbonyl monomer comprising a pendant pentafluorophenylester group, a catalyst, an initiator, an accelerator, and an optionalsolvent. The first mixture is then agitated with optional heating toeffect ring opening polymerization of the first cyclic carbonyl monomer,thereby forming a second mixture containing a biodegradable ROP polymer,while retaining the pendant pentafluorophenyl ester group. The ROPpolymer comprises a first polymer chain, the first polymer chaincomprising a first repeat unit, the first repeat unit comprising a sidechain comprising a pendant pentafluorophenyl ester group. In a specificembodiment, the side chain has the structure:

wherein the starred bond is linked to a backbone carbon of thebiodegradable first ROP polymer. In another embodiment, the first repeatunit of the first ROP polymer comprises a tetrahedral backbone carbon,the tetrahedral backbone carbon linked to i) a first side chaincomprising a pentafluorophenyl ester group, and ii) a second side chaingroup comprising a monovalent hydrocarbon radical. The monovalenthydrocarbon radical can comprise from 1 to 30 carbons. Morespecifically, the monovalent hydrocarbon radical is selected from thegroup consisting of methyl, ethyl, propyl, butyl and pentyl groups.

In an embodiment, the polymer retains at least 50%, and morespecifically at least 75%, and even more specifically at least 90% ofthe pentafluorophenyl ester groups relative to the repeat units derivedfrom the first cyclic carbonyl compounds.

As a non-limiting example, shown in Scheme C, MTC-PhF₅ undergoes ringopening polymerization in the presence of a suitable catalyst andnucleophilic initiator to form a ROP polymer, a polycarbonate.

In the naming notation used herein, 1-[P(Monomer1, Monomer 2,etc.)]_(w), “I” is the initiator, “[P( )]” indicates a polymer chainformed by ring opening polymerization of one or more cyclic carbonylcompounds listed in the parentheses, and w is the number of nucleophilicinitiator groups of the initiator. In the above example, the initiatoris benzyl alcohol, the initiator fragment is a benzyloxy group (BnO),and the name of the ROP homopolymer is BnOH—[P(MTC-PhF₅)]. The ROPpolymer can be prepared under mild conditions, achieving high molecularweight and low polydispersity (e.g., Example 16 below). Additionaly, theROP polymer can be prepared having substantially no metal contaminantwhen prepared with an organocatalyst. The wide utility and ease ofmanufacture of the first cyclic carbonyl monomers (and theircorresponding ROP polymers) makes these monomers considerably moreuseful than similar compounds comprising an acyl chloride group or asuccinimidyl ester group. The efficient method of forming ROP polymershaving an active pentafluorophenyl ester side chain group represents asignificant advancement in the state of the art in preparingfunctionalized ROP polymers.

The first mixture can comprise comonomers, including cyclic ethers,cyclic esters, and cyclic carbonates. Exemplary comonomers include:L-lactide, D-lactide, DL-lactide, beta-butyrolactone,delta-valerolactone, epsilon-caprolactone, trimethylene carbonate,methyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate, ethyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate, and other derivatives ofMTC-OH. These and other examples of cyclic carbonyl comonomers arelisted in Table 3.

TABLE 3

Organocatalysts for the ROP Polymerization.

Traditional metal containing catalysts for ring opening polymerizationare described above in Part I. Other ROP catalysts include metal-freeorganocatalysts, defined herein as a catalyst having none of thefollowing metals in the chemical formula of the organocatalyst:beryllium, magnesium, calcium, strontium, barium, radium, aluminum,gallium, indium, thallium, germanium, tin, lead, arsenic, antimony,bismuth, tellurium, polonium, and metals of Groups 3 to 12 of thePeriodic Table. This exclusion includes ionic and non-ionic forms of theforegoing metals. Metals of Groups 3 to 12 of the Periodic Table includescandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel,copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium,ruthenium, rhodium, palladium, silver, cadmium, lanthanum, cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium,hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold,mercury, actinium, thorium, protactinium, uranium, neptunium, plutonium,americium, curium, berkelium, californium, einsteinium, fermium,mendelevium, nobelium, lawrencium, rutherfordium, dubnium, seaborgium,bohrium, hassium, meitnerium, darmstadtium, roentgenium, andcopernicium. Organocatalysts can provide a platform to polymers havingcontrolled, predictable molecular weights and narrow polydispersities,and minimal metal contamination. Examples of organocatalysts for the ROPof cyclic esters, carbonates and siloxanes are 4-dimethylaminopyridine,phosphines, N-heterocyclic carbenes (NHC), bifunctional aminothioureas,phosphazenes, amidines, guanidines, and fluoroalcohols (such as mono-and bis-hexafluoroisopropanol compounds).

More specific metal-free organocatalysts for the ROP polymerization ofthe first cyclic monomer includeN-(3,5-trifluoromethyl)phenyl-N′-cyclohexyl-thiourea (TU):

Another metal-free ROP catalyst comprises at least one1,1,1,3,3,3-hexafluoropropan-2-ol-2-yl (HFP) group. Singly-donatinghydrogen bond catalysts have the formula (27):R²—C(CF₃)₂OH  (27),wherein R² represents a hydrogen or a monovalent radical having from 1to 20 carbons, for example an alkyl group, substituted alkyl group,cycloalkyl group, substituted cycloalkyl group, heterocycloalkyl group,substituted heterocycloalklyl group, aryl group, substituted aryl group,or a combination thereof. Exemplary singly-donating hydrogen bondingcatalysts are listed in Table 4.

TABLE 4

Doubly-donating hydrogen bonding catalysts have two HFP groups,represented by the general formula (28):

wherein R³ is a divalent radical bridging group containing from 1 to 20carbons, such as an alkylene group, a substituted alkylene group, acycloalkylene group, a substituted cycloalkylene group, aheterocycloalkylene group, substituted heterocycloalkylene group, anarylene group, a substituted arylene group, or a combination thereof.Representative double hydrogen bonding catalysts of formula (28) includethose listed in Table 5. In a specific embodiment, R² is an arylene orsubstituted arylene group, and the HFP groups occupy positions meta toeach other on the aromatic ring.

TABLE 5

In one embodiment, the catalyst is selected from the group consisting of4-HFA-St, 4-HFA-Tol, HFTB, NFTB, HPIP, 3,5-HFA-MA, 3,5-HFA-St, 1,3-HFAB,1,4-HFAB, and combinations thereof.

In particular, catalysts bearing 1,3-bis-HFP aromatic groups (such as1,3-HFAB) were found to be efficient in catalyzing the ROP of MTC-PhF₅without concomitant reaction of the pentafluorophenyl ester side chain.

Also contemplated are catalysts comprising HFP-containing groups boundto a support. In one embodiment, the support comprises a polymer, acrosslinked polymer bead, an inorganic particle, or a metallic particle.HFP-containing polymers can be formed by known methods including directpolymerization of an HFP-containing monomer (for example, themethacrylate monomer 3,5-HFA-MA or the styryl monomer 3,5-HFA-St).Functional groups in HFP-containing monomers that can undergo directpolymerization (or polymerization with a comonomer) include acrylate,methacrylate, alpha, alpha, alpha-trifluoromethacrylate,alpha-halomethacrylate, acrylamido, methacrylamido, norbornene, vinyl,vinyl ether, and other groups known in the art. Typical examples of suchpolymerizeable HFP-containing monomers may be found in: Ito et al.,Polym. Adv. Technol. 2006, 17(2), 104-115; Ito et al., Adv. Polym. Sci.2005, 172, 37-245; Ito et al., US20060292485; Maeda et al. WO2005098541;Allen et al. US20070254235; and Miyazawa et al. WO2005005370.Alternatively, pre-formed polymers and other solid support surfaces canbe modified by chemically bonding an HFP-containing group to the polymeror support via a linking group. Examples of such polymers or supportsare referenced in M. R. Buchmeiser, ed. “Polymeric Materials in OrganicSynthesis and Catalysis,” Wiley-VCH, 2003; M. Delgado and K. D. Janda“Polymeric Supports for Solid Phase Organic Synthesis,” Curr. Org. Chem.2002, 6(12), 1031-1043; A. R. Vaino and K. D. Janda “Solid Phase OrganicSynthesis: A Critical Understanding of the Resin”, J. Comb. Chem. 2000,2(6), 579-596; D.C. Sherrington “Polymer-supported Reagents, Catalysts,and Sorbents: Evolution and Exploitation—A Personalized View,” J. Polym.Sci. A. Polym. Chem. 2001, 39(14), 2364-2377; and T. J. Dickerson et al.“Soluble Polymers as Scaffold for Recoverable Catalysts and Reagents,”Chem. Rev. 2002, 102(10), 3325-3343. Examples of linking groups includeC₁-C₁₂ alkyl, C₁-C₁₂ heteroalkyl, an ether group, a thioether group, anamino group, an ester group, an amide group, or a combination thereof.Also contemplated are catalysts comprising charged HFP-containing groupsbound by ionic association to oppositely charged sites on a polymer or asupport surface.

The ROP reaction mixture comprises at least one catalyst and, whenappropriate, several catalysts together. The ROP catalyst is added in aproportion of 1/20 to 1/40,000 moles relative to the cyclic compounds,and preferably of 1/1,000 to 1/20,000 moles.

Accelerators for the ROP Polymerization

A nitrogen base can serve as catalyst or as an optional accelerator fora catalyst in a ring opening polymerization. Exemplary nitrogen base arelisted below and include pyridine (Py), N,N-dimethylaminocyclohexane(Me₂NCy), 4-N,N-dimethylaminopyridine (DMAP), trans1,2-bis(dimethylamino)cyclohexane (TMCHD),1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), (−)-sparteine, (Sp)1,3-bis(2-propyl)-4,5-dimethylimidazol-2-ylidene (Im-1),1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (Im-2),1,3-bis(2,6-di-1-propylphenyl(imidazol-2-ylidene (Im-3),1,3-bis(1-adamantyl)imidazol-2-ylidene (Im-4),1,3-di-1-propylimidazol-2-ylidene (Im-5),1,3-di-t-butylimidazol-2-ylidene (Im-6),1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene (Im-7),1,3-bis(2,6-di-1-propylphenyl)-4,5-dihydroimidazol-2-ylidene,1,3-bis(2,6-di-1-propylphenyl)-4,5-dihydroimidazol-2-ylidene (Im-8) or acombination thereof, shown in Table 6.

TABLE 6

In an embodiment, the accelerator has two or three nitrogens, eachcapable of participating as a Lewis base, as for example in thestructure (−)-sparteine. Stronger bases generally improve thepolymerization rate. In some instances, the nitrogen base is the solecatalyst for the ring opening polymerization, such as1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

Initiators for the ROP Polymerization

Initiators for the ring opening polymerization have been described aboveunder Part I. These generally include materials having one or morenucleophilic groups selected from the group consisting of alcohols,amines, and thiols. More particularly, the initiator for the ringopening polymerization of the first cyclic monomer bearing a pendantpentafluorophenyl ester is an alcohol. The alcohol initiator can be anysuitable alcohol, including mono-alcohol, diol, triol, or other polyol,with the proviso that the choice of alcohol does not adversely affectthe polymerization yield, polymer molecular weight, and/or the desirablemechanical and physical properties of the resulting ROP polymer. Thealcohol can be multi-functional comprising, in addition to one or morehydroxyl groups, a halide, an ether group, an ester group, an amidegroup, or other functional group. Additional exemplary alcohols includemethanol, ethanol, propanol, butanol, pentanol, amyl alcohol, caprylalcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol,tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol,heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, other aliphaticsaturated alcohols, cyclopentanol, cyclohexanol, cycloheptanol,cyclooctanol, other aliphatic cyclic alcohols, phenol, substitutedphenols, benzyl alcohol, substituted benzyl alcohol, benzenedimethanol,trimethylolpropane, a saccharide, poly(ethylene glycol), propyleneglycol, alcohol functionalized block copolymers derived from oligomericalcohols, alcohol functionalized branched polymers derived from branchedalcohols, or a combination thereof. Monomeric diol initiators includeethylene glycols, propylene glycols, hydroquinones, and resorcinols. Anexample of a diol initiator is BnMPA, derived from 2,2-dimethylolpropionic acid, a precursor used in the preparation of cyclic carbonatemonomers.

As indicated above, the ROP initiator can be a polymeric alcohol. Moreparticularly, the ROP initiator can be a polyether alcohol, such as apoly(alkylene glycol) or a mono end capped poly(alkylene glycol) whichincludes but is not limited to poly(alkylene glycol)s and mono endcapped poly(alkylene glycol)s. Such initiators serve to introduce a mainchain hydrophilic first block into the resulting first ROP polymer. Asecond block of the ROP polymer comprises a living chain segmentcomprising a side chain pentafluorophenyl ester group, the living chainsegment formed by ring opening polymerization of a first cyclic carbonylmonomer.

The polyether alcohol can be a poly(alkylene glycol) of the generalformula (32):HO—[C(R⁷)₂(C(R⁷)₂)_(a)C(R⁷)₂O]_(n)—H  (32),wherein a′ is 0 to 8, n is an integer from 2 to 10000, and each R⁷ isindependently a monovalent radical consisting of hydrogen and an alkylgroup of 1 to 30 carbons. Thus, the ether repeat unit comprises 2 to 10backbone carbons between each backbone oxygen. More particularly, thepoly(alkylene glycol) can be a mono end capped poly(alkylene glycol),represented by the formula (33):R⁸O—[C(R⁷)₂(C(R⁷)₂)_(a)C(R⁷)₂O]_(n)—H  (33),wherein R⁸ is a monovalent hydrocarbon radical comprising 1 to 20carbons.

As non-limiting examples, the polyether alcohol can be a poly(ethyleneglycol) (PEG), having the structure HO—[CH₂CH₂O]_(n)—H, wherein theether repeat unit CH₂CH₂O (shown in the brackets) comprises two backbonecarbons linked to a backbone oxygen. The polyether alcohol can also be apolypropylene glycol) (PPG) having the structure HO—[CH₂CH(CH₃)O]_(n)—H,where the ether repeat unit CH₂CH(CH₃)O comprises two backbone carbonslinked to a backbone oxygen with a methyl side-chain. An example of monoend capped PEG is the commercially available mono methyl end capped PEG(MPEG), wherein R⁸ is a methyl group. Other examples includepoly(oxetane), having the structure HO—[CH₂CH₂CH₂O]_(n)—H, andpoly(tetrahydrofuran), having the structure HO—[CH₂(CH₂)₂CH₂O]_(n)—H.

The mono end capped poly(alkylene glycol) can comprise more elaboratechemical end groups, represented by the general formula (34):Z′—[C(R⁷)₂(C(R⁷)₂)_(a′)C(R⁷)₂O]_(n-1)—H  (34),wherein Z′ is a monovalent radical including the backbone carbons andoxygen of the end repeat unit, and can have 2 to 100 carbons. Thefollowing non-limiting examples illustrate mono end-derivatization ofpoly(ethylene glycol) (PEG). As described above, one end repeat unit ofPEG can be capped with a monovalent hydrocarbon group having 1 to 20carbons, such as the mono methyl PEG (MPEG), wherein Z′ is MeOCH₂CH₂O—.The dash on the end of the MeOCH₂CH₂O— indicates the point of attachmentto the polyether chain. In another example, Z′ includes a thiol group,such as HSCH₂CH₂O—, or a thioether group, such as MeSCH₂CH₂O—. Inanother example, one end unit of PEG is an aldyhyde, wherein Z′ can beOCHCH₂CH₂O—. Treating the aldehyde with a primary amine produces animine, wherein Z′ is R⁹N═CHCH₂CH₂O—. R⁹ is a monovalent radical selectedfrom hydrogen, an alkyl group of 1 to 30 carbons, or an aryl groupcomprising 6 to 100 carbons. Continuing, the imine can be reduced to anamine, wherein Z′ is R⁹NHCH₂CH₂CH₂O—. In another example, one end repeatunit of PEG can be oxidized to a carboxylic acid, wherein Z′ isHOOCCH₂O—. Using known methods the carboxylic acid can be converted toan ester, wherein Z′ becomes R⁹OOCCH₂O—. Alternatively, the carboxylicacid can be converted to an amide, wherein Z′ becomes R⁹NHOCCH₂O—. Manyother derivatives are possible. In a particular embodiment, Z′ is agroup comprising a biologically active moiety that interacts with aspecific cell type. For example, the Z′ group can comprise a galactosemoiety which specifically recognizes liver cells. In this instance, Z′has the structure:

where L′ is a divalent linking group comprising 2 to 50 carbons. Thehyphen on the right side of L′ indicates the attachment point to thepolyether chain. Z′ can comprise other biologically active moieties suchas a mannose moiety.

The ring-opening polymerization can be performed with or without the useof a solvent, more particularly with a solvent. Optional solventsinclude dichloromethane, chloroform, benzene, toluene, xylene,chlorobenzene, dichlorobenzene, benzotrifluoride, petroleum ether,acetonitrile, pentane, hexane, heptane, 2,2,4-trimethylpentane,cyclohexane, diethyl ether, t-butyl methyl ether, diisopropyl ether,dioxane, tetrahydrofuran, or a combination comprising one of theforegoing solvents. When a solvent is present, a suitable cycliccarbonyl monomer concentration is about 0.1 to 5 moles per liter, andmore particularly about 0.2 to 4 moles per liter. In a specificembodiment, the reaction mixture for the ring-opening polymerizationcontains no solvent.

The ring-opening polymerization of the first cyclic monomer can beperformed at a temperature that is about ambient temperature or higher,more specifically a temperature from 15° C. to 200° C., and moreparticularly 20° C. to 60° C. Reaction times vary with solvent,temperature, agitation rate, pressure, and equipment, but in general thepolymerizations are complete within 1 to 100 hours.

Whether performed in solution or in bulk, the polymerizations areconducted in an inert (e.g., dry) atmosphere and at a pressure of from100 to 500 MPa (1 to 5 atm), more typically at a pressure of 100 to 200MPa (1 to 2 atm). At the completion of the reaction, the solvent can beremoved using reduced pressure.

The optional nitrogen base accelerator, when present, is present in anamount of 0.1 to 5.0 mol %, 0.1 to 2.5 mol %, 0.1 to 1.0 mol %, or 0.2to 0.5 mol %, based on total moles of cyclic carbonyl monomer.

The amount of initiator is calculated based on the equivalent molecularweight per nucleophilic initiating group in the initiator (e.g., hydroxygroups). The initiating groups are present in an amount of 0.001 to 10.0mol %, 0.1 to 2.5 mol %, 0.1 to 1.0 mol %, and 0.2 to 0.5 mol %, basedon total moles of cyclic carbonyl compound. For example, if themolecular weight of the initiator is 100 g/mole and the initiator has 2hydroxyl groups, the equivalent molecular weight per hydroxyl group is50 g/mole. If the polymerization calls for 5 mol % hydroxyl groups permole of monomer, the amount of initiator is 0.05×50=2.5 g per mole ofmonomer.

In a specific embodiment, the ring opening catalyst is present in anamount of about 0.2 to 20 mol %, the optional accelerator is present inan amount of 0.1 to 5.0 mol %, and the hydroxy groups of the initiatorare present in an amount of 0.1 to 5.0 mol % based on the equivalentmolecular weight per nucleophilic initiator group in the initiator.

The ring opening polymerization forms a ROP polymer comprising a livingpolymer chain. The living polymer chain can comprise a terminal hydroxylgroup, terminal thiol group, or terminal amine group, each of which caninitiate further ROP chain growth, if desired. At least one repeat unitof the ROP polymer comprises a side chain pentafluorophenyl ester group.

In an embodiment, the ROP polymer has a backbone comprising apolycarbonate homopolymer, a random polycarbonate copolymer, or a randompolyestercarbonate copolymer. The ROP polymer can comprise a linearpolymer, a cyclic polymer, a graft copolymer, and other polymertopologies. The ROP polymer can be a random copolymer, an alternatingcopolymer, a gradient copolymer, or a block copolymer. Blockcopolymerization may be achieved by sequentially polymerizing differentcyclic carbonyl monomers or by simultaneously copolymerizing monomerswith the appropriate reactivity ratios. The ROP polymer can comprisehydrophilic repeat units, hydrophobic repeat units, and combinationsthereof, thereby imparting amphiphilic properties to first ROP polymer.

In a preferred embodiment, the catalyst, accelerator, and reactionconditions are selected such that the growing chain end (a nucleophilicalcohol) will not react intramolecularly with a pendantpentafluorophenyl ester group of the same polymer chain to form a cyclicstructure or intermolecularly with a pendant pentafluorophenyl estergroup of another polymer chain. In this way, linear polymers withcontrolled polydispersities can be synthesized. At high conversions whenthe relative concentration of monomer is low, reaction with pendantpentafluorophenyl ester groups can occur with subsequent broadening ofthe polydispersity.

If the reaction conditions permit (e.g., when a strongly activatingcatalyst is used), the growing chain end (e.g., a nucleophilic alcohol)may also react with the pendant pentafluorophenyl ester side chaingroups of unreacted first cyclic carbonate monomers or the pendantpentafluorophenyl ester side chain groups of the same (i.e., anintramolecular reaction) or another polymer chain (i.e., anintermolecular reaction). Reaction with the pendant pentafluorophenylester side chain groups of unreacted first cyclic carbonate monomerswill result in the formation of a macromer which may be subsequently bepolymerized to make a comb or graft polymer. Intramolecular reaction mayproduce cyclic structures, while intermolecular reaction may afford abranched polymer. If strongly forcing reaction conditions are used, thegrowing chain end may also react with the carbonyl structures (e.g.,ester, carbonate, etc.) in the polymer main chains and lead tomacrocyclization or segmental exchange (by transesterification forexample). Such conditions should be avoided if one wants to producepolymers with controlled molecular weights and polydispersities.

Alternatively, if a comonomer comprising additional nucleophilic groups(e.g., OX-BHMP) is used in the preparation of the first ROP polymercomprising a pentafluorophenyl ester side chain group, then theseadditional nucleophilic groups may serve as initiator groups (whichinitiate polymer chains) as well as nucleophilic groups which can reactwith the pendant pentafluorophenyl ester side chain groups. If theadditional nucleophilic groups only serve as initiator groups, theresult of the synthesis may be a first ROP polymer comprising apentafluorophenyl ester side chain group with a branched, hyperbranched,comb, bottlebrush, or other such structure. If the reaction conditionspermit, the additional nucleophilic groups may also react with thependant pentafluorophenyl ester side chain groups of unreacted firstcyclic carbonate monomers or the pendant pentafluorophenyl ester sidechain groups of the same (i.e., an intramolecular reaction) or anotherpolymer chain (i.e., an intermolecular reaction). Intramolecularreaction may produce cyclic structures, while intermolecular reactionmay afford a polymeric crosslinked network or gel (which may or may nothave any residual pentafluorophenyl ester side chain groups remaining).Again, strongly forcing reaction conditions can allow these nucleophilicgroups to also react with the carbonyl structures (e.g., ester,carbonate, etc.) in the polymer main chains, although this is generallyundesirable.

The first ROP polymer can be a homopolymer, copolymer, or blockcopolymer. The polymer can have a number-average molecular weight ofusually 1,000 to 200,000, more particularly 2,000 to 100,000, and stillmore particularly 5,000 to 80,000. In an embodiment, the ROP polymerchain has a number average molecular weight M_(n) of 10000 to 20000g/mole. In an embodiment, the ROP polymer chains also have a narrowpolydispersity index (PDI), generally from 1.01 to 1.35, moreparticularly 1.1 to 1.30, and even more particularly 1.1 to 1.25.

Part II, Method 4. Functionalization of the First ROP Polymer

Further disclosed is a method (Method 4) of converting the first ROPpolymer comprising a pentafluorophenyl ester side chain group into afunctionalized second polymer by reaction of the pentafluorophenyl esterside chain group with a suitable nucleophile, without disruption of thebackbone carbonyl moiety of the first ROP polymer. As a non-limitingexample, the functionalization of first ROP polymer BnOH—P(MTC-PhF₅)using nucleophile R′—XH is illustrated in Scheme D.

R″—XH is a nucleophile selected from the group consisting of alcohols,amines, thiols, and combinations thereof, wherein R″ is withoutrestriction with the proviso that a useful polymer is obtained. In anembodiment, R″ comprises 1 to 10000 carbons. The functionalized secondpolymer can be prepared having essentially no remainingpentafluorophenyl ester groups.

The method (Method 4) comprises forming a first mixture comprising theROP polymer comprising a pentafluorophenyl ester side chain group, anoptional second catalyst, a nucleophile selected from the groupconsisting of alcohols, amines, thiols, and combinations thereof, and anoptional solvent. The first mixture is then agitated and optionallyheated to effect reaction of the pentafluorophenyl ester with thenucleophile, thereby forming a second mixture containing thefunctionalized second polymer comprising a pendant functional groupselected from the group consisting of alcohol based esters other than apentafluorophenyl ester, amides, thioesters, and combinations thereof,and pentafluorophenol byproduct.

The first ROP polymer can be treated with a variety of nucleophiles toform a functionalized second polymer. Exemplary nucleophiles include butare not limited to polymeric and non-polymeric alcohols, thiols, andamines described further above under Method 2 and Method 3. When thenucleophile is a polyether alcohol, the functionalized second polymercomprises a side chain ester group comprising a hydrophilic polyetherchain.

The nucleophile can further comprise isotopically enriched versions ofcarbon, nitrogen and hydrogen, including for example ¹³C, ¹⁴C, ¹⁵N,deuterium, or combinations thereof. The amine can also comprise aradioactive moiety including a heavy metal radioactive isotope. Method 2described above can also include a nucleophile comprising isotopicallyenriched versions of carbon, nitrogen, and hydrogen, as well as aradioactive moiety.

The nucleophile can further comprise additional reactive functionalgroups including alcohol, amine, thiol, vinyl, allyl, propargyl,acetylene, azide, glycidyl, furan, furfuryl, acrylate, methacrylate,vinyl phenyl, vinyl ketone, vinyl ether, crotyl, fumarate, maleate,maleimide, butadiene, cyclopentadiene, cyclohexadiene, and derivativesthereof. These additional reactive groups may serve as sites foradditional subsequent modification through Diels-Alder or Huisgen1,3-dipolar cycloadditions, for example.

The nucleophile comprising an alcohol group, amine group, thiol group,or combination thereof can be attached to a larger structure includingoligomers, polymers, biomacromolecules, particles, and functionalizedsurfaces. Non-limiting oligomeric and polymeric structures includelinear, branched, hyperbranched, cyclic, dendrimeric, block, graft,star, and other known polymer structures. Non-limiting biomacromoleculesinclude carbohydrates, proteins, DNA, RNA, lipids, phospholipids.Particles comprising the nucleophilic groups can have an averagediameter ranging from less than 1 nanometer to hundreds of micrometers.Non-limiting functionalized surfaces include silica, alumina, andpolymeric resins such as those commonly used for chromatography andfunctionalized polymeric beads such as those commonly used forsolid-phase synthesis.

When multifunctional nucleophiles are used (e.g., diamines, triamines,diols, triols, or aminoalcohols), the functionalization reaction canresult in the formation of a functionalized second polymer comprising acrosslinked network or gel. The multifunctional nucleophile can therebyserve as a crosslinking agent by reacting with pentafluorophenyl estergroups from different polymer chains.

Nanoparticulate nucleophiles comprising an alcohol, amine, thiol, orcombination thereof, can have an average diameter of from 1 nm to 500nm. The nanoparticles can comprise both organic and inorganicnanoparticles, including those functionalized with ligands orstabilizing polymers. Organic nanoparticles can include, but are notlimited to, crosslinked polymeric nanoparticles, dendrimers, and starpolymers. Inorganic nanoparticles include, but are not limited to,metallic nanoparticles (e.g., gold, silver, other transition metals, andGroup 13 to Group 16 metals of the Periodic Table), oxide nanoparticles(e.g., alumina, silica, hafnia, zirconia, zinc oxide), nitridenanoparticles (e.g., titanium nitride, gallium nitride), sulfidenanoparticles (e.g., zinc sulfide) semiconducting nanoparticles (e.g.,cadmium selenide). Functionalized surfaces include, but are not limitedto, surfaces functionalized with self-assembled monolayers.

When multifunctional nucleophiles are used (e.g., diamines, triamines,diols, triols, aminoalcohols . . . etc.), the functionalization reactioncan result in the formation of a functionalized second polymercomprising a crosslinked network or gel. The multifunctional nucleophilecan thereby serve as a crosslinking agent by reacting withpentafluorophenyl ester groups from different polymer chains.

The reaction of the first ROP polymer with a nucleophile is generallyconducted in a reactor under inert atmosphere such as nitrogen or argon.The reaction can be performed using an inactive solvent such as benzene,toluene, xylene, dioxane, chloroform and dichloroethane, methylenechloride, tetrahydrofuran, acetonitrile, N,N-dimethyl formamide,dimethylsulfoxide, dimethyl acetamide, or mixtures thereof. Thefunctionalization reaction temperature can be from 20° C. to 250° C.Generally, the reaction mixture is agitated at room temperature andatmospheric pressure for 0.5 to 72 hours to effect complete conversionof the pentafluorophenyl ester groups. Subsequently, an additionalnucleophile and catalyst can be added to the second mixture to effectfurther functionalization of any non-reacted pentafluorophenyl estergroups. Alternatively, an additional nucleophile and coupling reagentcan be added to the second mixture to effect functionalization of anycarboxylic acid groups that have formed by hydrolysis of the pendantpentafluorophenyl ester groups.

Typically, the first mixture comprises a solvent, although this is notrequired. Depending on the solvent, the pentafluorophenol byproduct canin some instances precipitate directly from the reaction mixture as itis formed. Generally, however, the functionalized second polymer can beisolated by precipitation using a suitable non-solvent such asisopropanol. In this manner the functionalized second polymer can beobtained in a yield of about 50% to about 100%, more particularly about70% to 100%, even more particularly about 80% to 100%.

The optional catalyst of the first mixture (Method 4) can be selectedfrom typical catalysts for transesterifications, conversions of estersto amides, or conversion of esters to thioesters. These include organiccatalysts and inorganic catalysts, in particular the above describedcatalysts, and most specifically cesium fluoride. When used in the firstmixture, the catalyst can be present in an amount of 0.02 to 1.00 molesper mole of cyclic carbonyl monomer used to prepare the first ROPpolymer, more particularly 0.05 to 0.50 moles per mole of the cycliccarbonyl monomer used to prepare the first ROP polymer, and even moreparticularly 0.15 to 0.25 moles per mole of the cyclic carbonyl monomerused to prepare the ROP polymer.

In general, the efficacy of the substitution reactions proceed inaccordance with the nucleophilicity of the nucleophiles. For example,stronger nucleophiles such as primary amines are more effective thanweaker nucleophile such as primary alcohols. In addition, stericallyunencumbered nucleophiles react more readily than sterically hinderednucleophiles. For example, substitution using aniline (PhNH₂) was moreeffective than with N-ethyl aniline (PhN(Et)H), a secondary aromaticamine.

In an additional embodiment, the polymerization to form the first ROPpolymer (Method 3) comprising a pendant pentafluorophenyl ester group,and the subsequent reaction of the first ROP polymer with a nucleophileto form a functionalized second polymer (Method 4) by displacement ofthe pentafluorophenoxy group of the pentafluorophenyl ester, areconducted step-wise in a single reaction vessel, without an intermediatestep to isolate the first ROP polymer bearing the side chainpentafluorophenyl ester groups.

The above-described methods provide a controlled process for introducinga wide range of functionality and connectivity into polymers formed byring-opening polymerizations of cyclic carbonyl compounds comprising apendant pentafluorophenyl ester group. The first ROP polymer and thefunctionalized second polymer are particularly advantageous because theycan be obtained with minimal metal contaminant when produced by anorganocatalyst whose chemical formula has none of the following metals:beryllium, magnesium, calcium, strontium, barium, radium, aluminum,gallium, indium, thallium, germanium, tin, lead, arsenic, antimony,bismuth, tellurium, polonium, and metals of Groups 3 to 12 of thePeriodic Table.

In preferred embodiments, the first ROP polymer and/or thefunctionalized second polymer contains no more than 1000 ppm (parts permillion), preferably no more than 100 ppm, more preferably no more than10 ppm, and still more preferably no more than 1 ppm, of everyindividual metal of the group consisting of beryllium, magnesium,calcium, strontium, barium, radium, aluminum, gallium, indium, thallium,germanium, tin, lead, arsenic, antimony, bismuth, tellurium, polonium,and metals of Groups 3 to 12 of the Periodic Table. For example, if thelimit is no more than 100 ppm, then each of the foregoing metals has aconcentration not exceeding 100 ppm in the first ROP polymer, thefunctionalized second polymer, or both. When an individual metalconcentration is below detection capability or has a concentration ofzero parts, the concentration is expressed as 0 ppm. In anotherembodiment, every individual metal of the group consisting of beryllium,magnesium, calcium, strontium, barium, radium, aluminum, gallium,indium, thallium, germanium, tin, lead, arsenic, antimony, bismuth,tellurium, polonium, and metals of Groups 3 to 12 of the Periodic Tablehas a concentration of 0 ppm to 1000 ppm, 0 ppm to 500 ppm, 0 ppm to 100ppm, 0 ppm to 10 ppm, or even more particularly 0 ppm to 1 ppm in thefirst ROP polymer, the functionalized second polymer, or both. Forexample, if the concentration can have a value in the range of 0 ppm to100 ppm (inclusive), then each of the foregoing metals has aconcentration of 0 ppm to 100 ppm in the first ROP polymer, thefunctionalized second polymer, or both. In another embodiment, the firstROP polymer, the functionalized second polymer, or both comprises lessthan 1 ppm of every individual metal of the group consisting ofberyllium, magnesium, calcium, strontium, barium, radium, aluminum,gallium, indium, thallium, germanium, tin, lead, arsenic, antimony,bismuth, tellurium, polonium, and metals of Groups 3 to 12 of thePeriodic Table. To be clear, if the limit is less than 1 ppm, then eachof the foregoing metals has a concentration of less than 1 ppm in thefirst ROP polymer, the functionalized second polymer, or both.

The polymer products of the ROP polymerizations described in Part II canalso be applied to conventional molding methods such as compressionmolding, extrusion molding, injection molding, hollow molding and vacuummolding, and can be converted to molded articles such as various parts,receptacles, materials, tools, films, sheets and fibers. A moldingcomposition can be prepared comprising the polymer and variousadditives, including for example nucleating agents, pigments, dyes,heat-resisting agents, antioxidants, weather-resisting agents,lubricants, antistatic agents, stabilizers, fillers, strengthenedmaterials, fire retardants, plasticizers, and other polymers. Generally,the molding compositions comprise 30 wt. % to 100 wt. % or more of thepolymer based on total weight of the molding composition. Moreparticularly, the molding composition comprises 50 wt. % to 100 wt. % ofthe polymer.

The first ROP polymer and the functionalized second polymer described inPart II can also be formed into free-standing or supported films byknown methods. Non-limiting methods to form supported films include dipcoating, spin coating, spray coating, doctor blading. Generally, suchcoating compositions comprise 0.01 wt. % to 90 wt. % of the polymerbased on total weight of the coating composition. More particularly, themolding composition comprises 1 wt. % to 50 wt. % of the polymer basedon total weight of the coating composition. The coating compositionsgenerally also include a suitable solvent necessary to dissolve thepolymer product.

The coating compositions of Part II can also further include otheradditives selected so as to optimize desirable properties, such asoptical, mechanical, and/or aging properties of the films. Non-limitingexamples of additives include surfactants, ultraviolet light absorbingdyes, heat stabilizers, visible light absorbing dyes, quenchers,particulate fillers, and flame retardants. Combinations of additives canalso be employed.

The second cyclic carbonyl compounds can also bear polymerizeablefunctional groups which can be polymerized by ROP, free-radical, CRP, orother polymerization techniques, such as or controlled radicalpolymerization techniques, including nitroxide-mediated radicalpolymerization, atom transfer radical polymerization (ATRP), andreversible addition-fragmentation polymerization (RAFT). These monomerscan be polymerized through the cyclic carbonyl group, the polymerizeablefunctional group, or both. The cyclic carbonyl group and thepolymerizeable functional group can be polymerized in any order (e.g.,ROP of a cyclic carbonate and then polymerization of the functionalgroup, vice versa, or simultaneously). Alternatively, the functionalgroup can be polymerized (or copolymerized) to afford a polymer withpendant cyclic carbonyl groups. These cyclic carbonyl groups can then bereacted to append groups to the polymer. For example, ring-openingreactions of cyclic carbonates with primary or secondary amines are wellknown to produce hydroxy carbamates.

In the following Examples of Part II, Examples 16, 19-22 and 26demonstrate Method 3 of ring opening polymerization of a first cycliccarbonyl monomer bearing a pendant pentafluorophenyl ester group. Theresulting first ROP polymer comprises a repeat unit comprising a sidechain pentafluorophenyl ester group. Examples 17, 18, and 23-24,demonstrate Method 4 of forming a functionalized second polymer byconverting the pentafluorophenyl ester side chain group of the first ROPpolymer into a different side chain ester or amide using variousnucleophiles. Example 25 demonstrates the preparation of first cycliccarbonyl monomer ETC-PhF₅, the 5-ethyl analogue of MTC-PhF₅.

Part II. Examples 16-26.

Unless indicated otherwise, parts are parts by weight, temperature is in° C. and pressure is at or near atmospheric.Bis(pentafluorophenyl)carbonate was obtained from Central Glass Co.,Ltd. (Japan). All the other starting materials were obtained (inanhydrous grade if possible) from Aldrich Chemical Co. ¹H, ¹³C and ¹⁹Fnuclear magnetic resonance (NMR) spectra were obtained at roomtemperature on a Bruker Avance 400 spectrometer. Table 7 lists materialsused in the examples.

TABLE 7 Name Description Company bis-MPA bis(2,2-methylol) propionicacid Aldrich PFC bis(pentafluorophenyl) carbonate Central Glass Co.,Ltd. 1,3-HFAB 1,3-bis(1,1,1,3,3,3-hexafluoro-2- Central Glass Co.,hydroxy-prop-2-yl)benzene; catalyst Ltd. (−)- Accelerator Aldrichsparteine CsF Cesium fluoride; catalyst Aldrich

Example 16 Homopolymerization of pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅)

In a dry 5 mL vial, pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) (301 mg, 0.924 mmol)was combined with1,3-bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-prop-2-yl)benzene (1,3-HFAB)(19 mg, 0.0462 mmol, 0.05 eq.), (−)-sparteine (22 microliters, 0.12eq.), and benzyl alcohol (1 microliters, 0.01 eq.) were dissolved inmethylene chloride (1.5 mL) and stirred at room temperature. After eighthours, conversion had reached about 70%. The polymer weight averagemolecular weight (M_(w)) increases linearly versus conversion (as shownin the graph of FIG. 13) which is characteristic of a controlled livingpolymerization. Only at high conversion does the molecular weightdeviate, presumably due to intermolecular coupling of the terminalhydroxyl group with pentafluorophenyl ester groups of other polymerchains. Despite this small amount of intramolecular interaction, thepolydispersity index (PDI) remains reasonably narrow. At 70% conversion,the initial ROP polymer BnOH-[P(MTC-PhF₅)] had M_(n)=9500 g/mol,M_(w)=12000 g/mol, and PDI=1.26. Approximately 87% of thepentafluorophenyl ester groups were retained in the initial ROP polymer.

Example 17 Functionalization of BnOH—[P(MTC-PhF₅)] with3-(trifluoromethyl)benzyl amine

Under a dry nitrogen atmosphere, BnO—[P(MTC-PhF₅)] (0.20 g, 0.84 mmol)and 3-(trifluoromethyl)benzyl amine (0.15 g, 0.86 mmol, 1.0 eq.) weredissolved in dry tetrahydrofuran (THF) (0.6 mL). The mixture was stirredfor 5.5 hours at room temperature. The functionalized second polymer(SP-1) was isolated by a precipitation in hexane. Percent substitution:95%. Residual pentafluorophenyl ester: 0%. M_(n)=19,200. M_(n)=65,500g/mol. PDI=3.41.

Example 18 Functionalization of BnO—[H4P(MTC-PhF₅)] with3-(trifluoromethyl)benzyl Alcohol

Under a dry nitrogen atmosphere, BnOH—[P(MTC-PhF₅)] (0.20 g, 0.84 mmol),3-(trifluoromethyl)benzyl alcohol (0.16 g, 0.92 mmol, 1.05 eq.), andcesium fluoride (0.1 g, 0.66 mmol, 0.8 eq.) were dissolved in drytetrahydrofuran (THF) (0.6 mL). The mixture was stirred for 20 hours atroom temperature. The functionalized second polymer (SP-2) was isolatedby a precipitation in hexane. Percent substitution: 50%. Residualpentafluorophenyl ester: 0%. Approximately 50% of the pentafluorophenylester groups were lost, presumably due to hydrolysis to carboxylic acidgroups during the reaction or polymer isolation. This may have occurredduring the reaction due to residual water in the3-(trifluoromethyl)benzyl alcohol or insufficient drying of the reactionsolvent or reaction apparatus or during the precipitation and isolationprocess. M_(n)=12,000 g/mol. M_(w)=20,100 g/mol. PDI=1.68.

Example 19 Copolymerization of pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) and Ethyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-Et)

In a dry 2 mL vial, pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) (38.5 mg, 0.118mmol, 0.1 eq.), ethyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-Et)(200 mg, 1.06 mmol, 0.9 eq.),1,3-bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-prop-2-yl)benzene (1,3-HFAB)(24 mg, 0.05 eq.), (−)-sparteine (7 microliters, 0.025 eq.), and benzylalcohol (1.2 microliters, 0.01 eq.) were dissolved in deuterochloroform(750 mg) and stirred at room temperature. The molar ratio of MTC-PhF₅ toMTC-Et was 10:90. A graph of the monomer conversion versus time in FIG.14 reveals the unequal reactivities of these two monomers towardspolymerization. From this graph, the pentafluorophenyl ester monomerMTC-PhF₅ (diamonds) is incorporated much more rapidly than the ethylester monomer (triangles). As a result of this asymmetric incorporationrate, the resulting first polymer BnOH—[P(MTC-PhF₅-co-MTC-Et)] is likelya gradient or block-like copolymer rather than the purely randomcopolymer indicated by the bracketed ladder formula above. After 200hours, the product BnOH-[P(MTC-PhF₅-co-MTC-Et)] had a M_(n) of 17600g/mol, a M_(w) of 26500 g/mol, and a PDI of 1.51.

Example 20 Copolymerization of Pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) and L-lactide (LLA)

In a dry 5 mL vial, pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) (65.2 mg, 0.20 mmol,0.2 eq.), L-lactide (115.2 mg, 0.8 mmol, 0.8 eq.),1,3-bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-prop-2-yl)benzene (1,3-HFAB)(22.5 mg, 0.055 eq.), (−)-sparteine (5.7 microliters, 0.025 eq.), andbenzyl alcohol (1 microliter, 0.01 eq.) were dissolved indeuterochloroform (1 mL) and stirred at room temperature. The molarratio of MTC-PhF₅ to L-lactide was 20:80. A graph of the monomerconversion versus time (FIG. 15) again reveals the unequal reactivitiesof these two monomers towards polymerization. In this instance, however,the pentafluorophenyl ester monomer MTC-PhF₅ (diamonds) is incorporatedmuch more slowly than the L-lactide (squares). As a result of thisasymmetric incorporation rate, the resulting initial polymerBnOH—[P(MTC-PhF₅-co-LLA)] is likely a gradient or block-like copolymerrather than a purely random copolymer, as indicated by the bracketedladder formula. After 23 hours, the initial polymerBnOH—[P(MTC-PhF₅-co-LLA)] had a M_(n) of 23600 g/mol, a M_(w) of 27000g/mol, and a PDI of 1.15.

Example 21 Block copolymerization of Pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) and L-lactide (LLA)

To a dry 100 mL flask, L-lactide (1.92 g, 13.4 mmol, 0.8 eq.),1,3-bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-prop-2-yl)benzene (1,3-HFAB)(342 mg, 0.055 eq.), (−)-sparteine (98 mg, 0.025 eq.), and benzylalcohol (18 mg, 0.166 mmol, 0.0123 eq.) were combined indeuterochloroform (15 mL) and stirred at room temperature. After 5hours, pentafluorophenyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate(MTC-PhF₅) (1.09 g, 3.34 mmol, 0.2 eq.) was added and the solutionallowed to stir at room temperature for an additional 20 hours. Theblock copolymer BnOH—[P(LLA-b-MTC-PhF₅)] was isolated via precipitationfrom 2-propanol and had a M_(n) of 22200 g/mol, a M_(w) of 28800 g/moland a PDI of 1.29. Ratio of x:y=4.1:1. Approximately, 70% of thepentafluorophenyl ester groups were retained after isolation.

Example 22 Block Copolymerization of pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) and L-lactide (LLA)

This polymerization is a repeat of Example 21 using 16% by weightadditional benzyl alcohol initiator. To a dry 100 mL flask, L-lactide(1.92 g, 13.4 mmol, 0.8 eq.),1,3-bis(1,1,1,3,3,3-hexafluoro-2-hydroxy-prop-2-yl)benzene (1,3-HFAB)(342 mg, 0.055 eq.), (−)-sparteine (98 mg, 0.025 eq.), and benzylalcohol (21 mg, 0.194 mmol, 0.0144 eq.) were combined in dichloromethane(15 mL) and stirred at room temperature. After 14 hours,pentafluorophenyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅)(1.09 g, 3.34 mmol, 0.2 eq.) was added and the solution was allowed tostir at room temperature for an additional 7 hours. The block copolymerBnOH—[P(LLA-b-MTC-PhF₅)] was isolated via precipitation from 2-propanol,and had a M_(n) of 18800 g/mol, a M_(w) of 21600 g/mol and a PDI of1.15. Ratio of x:y=4.9:1. Approximately, 99% of the pentafluorophenylester groups were retained after isolation.

Example 23 Functionalization of Poly(pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate-b-1-lactide), referred to aboveas BnOH—[P(LLA-b-MTC-PhF₅)], with 3-(trifluoromethyl)benzyl amine.

Under a dry nitrogen atmosphere, initial polymerBnOH—[P(LLA-b-MTC-PhF₅)] (503 mg, 0.389 mmol (as-C₆F₅ ester)) and3-(trifluoromethyl)benzyl amine (103 mg, 0.585 mmol, 1.5 eq.) weredissolved in dry N,N-dimethylformamide (DMF) (0.56 g). The mixture wasstirred for 5 hours at room temperature. After the reaction, thefunctionalized second polymer SP-3 was precipitated from methanol.Properties of second polymer SP-3: Percent substitution: 95%. Residualpentafluorophenyl ester: 0%. M_(n)=23,500 g/mol. M_(w)=32,000 g/mol.PDI=1.36. Ratio of x:y=4.1:1.

Example 24 Functionalization of Poly(pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate-b-1-lactide), referred to aboveas BnOH—[P(LLA-b-MTC-PhF₅)] with 3-(trifluoromethyl)benzyl Alcohol

Under a dry nitrogen atmosphere, initial polymerBnOH—[P(LLA-b-MTC-PhF₅)] (250 mg, 0.194 mmol (as-C₆F₅ ester)),3-(trifluoromethyl)benzyl alcohol (235 mg, 1.33 mmol, 6.9 eq.), andcesium fluoride (27 mg, 0.714 mmol, 0.9 eq.) were dissolved in drytetrahydrofuran (THF). The mixture was stirred for 2 days at roomtemperature. After the reaction, the functionalized second polymer SP-4was precipitated from dichloromethane-hexane mixture. Properties ofsecond polymer SP-4: Percent substitution: 59%. Residualpentafluorophenyl ester: 0%. Ratio of x:y=4.1:1. M_(n)=14,300 g/mol.M_(n)=19,600 g/mol. PDI=1.37.

Example 25

Preparation of ETC-PhF₅.

To a 100 mL round bottom flask, 1,1-bis(hydroxymethyl)butanoic acid (3.0g, 20 mmol) was combined with bis(pentafluorophenyl carbonate) (18.4 g,47 mmol, 2.3 eq) and cesium fluoride (0.92 g, 6.0 mmol) intetrahydrofuran (29 mL) and stirred for 20 hours at room temperature.The reaction was concentrated (bath temperature: 30° C. pressure: ˜100mm Hg), and redissolved in methylene chloride. Upon sitting (−10 min)the pentafluorophenol byproduct fell out of solution and could berecovered. After removal of the byproduct by filtration, the motherliquid was washed with aqueous sodium bicarbonate (3×50 mL) (pH ofaqueous layer ˜8) and brine (1×50 mL). The organic layer was separatedand dried over anhydrous sodium sulfate. After filtration, the solutionwas concentrated to give the crude product.

The crude was dissolved in ethyl acetate (6 mL) at 65° C. n-Hexane (24mL) was added to the solution at the same temperature after which thesolution was slowly cooled to room temperature. After stirring thesolution over night, the crystal was separated by filtration (5.1 g, 75%yield).

Example 26 Comparison of the Rate of Homopolymerization ofPentafluorophenyl 5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅)and Pentafluorophenyl 5-ethyl-2-oxo-1,3-dioxane-5-carboxylate (ETC-PhF₅)

In a NMR tube, pentafluorophenyl5-methyl-2-oxo-1,3-dioxane-5-carboxylate (MTC-PhF₅) or pentafluorophenyl5-ethyl-2-oxo-1,3-dioxane-5-carboxylate (ETC-PhF₅) (0.07 g, 0.2 mmol)was combined with1,3-bis(1,1,3,3,3-hexafluoro-2-hydroxy-prop-2-yl)benzene (1,3-HFAB)(22.5 mg, 0.27 eq.), (−)-sparteine (5.7 microliters, 0.125 eq.), andbenzyl alcohol (0.2 microliters, 0.02 eq.) were dissolved indeuterochloroform (0.75 g). The reaction was observed by ¹H and ¹⁹F NMR.The % conversion at various time intervals is listed in Table 8. FromTable 8, the ethyl substituted version ETC-PhF₅ displays significantlyslower reaction kinetics than the methyl substituted version MTC-PhF₅.The size of the substituent group in the 5 position can be used to tunethe reactivity of the cyclic carbonate monomers. In such a manner, therelative reactivity of the pentafluorophenyl ester-functionalized cycliccarbonate can be balanced with that of a comonomer in order to attainrandom copolymers, for example.

TABLE 8 Time % Conversion of % Conversion of [min] MTC-PhF₅ ETC-PhF₅ 7357 9 123 84 418 30 1321 63 1691 73

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. When a range is used to express apossible value using two numerical limits X and Y (e.g., a concentrationof X ppm to Y ppm), unless otherwise stated the value can be X, Y, orany number between X and Y.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiments were chosen and described in order to best explain theprinciples of the invention and their practical application, and toenable others of ordinary skill in the art to understand the invention.

What is claimed is:
 1. A biodegradable polymer, comprising: a chainfragment; and a first polymer chain; wherein i) the chain fragmentcomprises a first backbone heteroatom, the first backbone heteroatomlinked to a first end unit of the first polymer chain, the firstbackbone heteroatom selected from the group consisting of oxygen,nitrogen, and sulfur, ii) the first polymer chain comprises a second endunit comprising a nucleophilic group selected from the group consistingof hydroxy group, primary amine groups, secondary amine groups, andthiol group, and iii) the first polymer chain comprises a first repeatunit comprising a) a backbone functional group selected from the groupconsisting of carbonate, ureas, carbamates, thiocarbamates,thiocarbonate, and dithiocarbonate, and b) a tetrahedral backbonecarbon, the tetrahedral backbone carbon being linked to a first sidechain comprising a pentafluorophenyl ester group.
 2. The biodegradablepolymer of claim 1, wherein the first repeat unit comprises a carbonatebackbone functional group.
 3. The biodegradable polymer of claim 1,wherein the first backbone heteroatom is oxygen.
 4. The biodegradablepolymer of claim 1, wherein the first backbone heteroatom is nitrogen.5. The biodegradable polymer of claim 1, wherein the first backboneheteroatom is sulfur.
 6. The biodegradable polymer of claim 1, whereinthe second end unit comprises a hydroxy group.
 7. The biodegradablepolymer of claim 1, wherein the second end unit comprises a primaryamine group.
 8. The biodegradable polymer of claim 1, wherein the secondend unit comprises an secondary amine group.
 9. The biodegradablepolymer of claim 1, wherein the second end unit comprises an thiolgroup.
 10. The biodegradable polymer of claim 1, wherein the firstrepeat unit comprises a carbamate backbone functional group.
 11. Thebiodegradable polymer of claim 1, wherein the first repeat unitcomprises a urea backbone functional group.
 12. The biodegradablepolymer of claim 1, wherein the side chain comprising thepentafluorophenyl ester group has the structure

wherein the starred bond is linked to the tetrahedral backbone carbon ofthe first repeat unit.
 13. The biodegradable polymer of claim 1, whereinthe tetrahedral backbone carbon is further linked to a second side chaingroup comprising a monovalent hydrocarbon radical.
 14. The biodegradablepolymer of claim 1, wherein the biodegradable polymer contains no metalselected from the group consisting of beryllium, magnesium, calcium,strontium, barium, radium, aluminum, gallium, indium, thallium,germanium, tin, lead, arsenic, antimony, bismuth, tellurium, polonium,and metals of Groups 3 to 12 of the Periodic Table having aconcentration in the biodegradable polymer greater than 100 ppm.
 15. Thebiodegradable polymer of claim 1, wherein the polymer undergoes 60%biodegradation within 180 days in accordance with ASTM D6400.
 16. Thebiodegradable polymer of claim 1, wherein the nucleophilic group of thesecond end unit is capable of initiating a ring opening polymerization.17. The biodegradable polymer of claim 1, wherein the first polymerchain comprises a second repeat unit, the second repeat unit comprisinga second backbone functional group selected from the group consisting ofesters, carbonate, ureas, carbamates, thiocarbamates, thiocarbonate, anddithiocarbonate.
 18. The biodegradable polymer of claim 17, wherein thesecond backbone functional group comprises an ester.
 19. Thebiodegradable polymer of claim 17, wherein the second backbonefunctional group comprises a carbonate.
 20. The biodegradable polymer ofclaim 17, wherein the second backbone functional group comprises acarbamate.
 21. The biodegradable polymer of claim 17, wherein the secondbackbone functional group comprises a urea.